Gateway Series

A Gateway Series is a series that introduces a significant niche of viewers to a genre that is new to them, and that is a positive enough introduction for them to hunt down other examples of the genre.

Trope Namer: In the drug world, a gateway drug is a drug that entices you or makes it easier to try other drugs. This name is mostly used by anti-drug programs, so there is debate about whether gateway drugs are real. But gateway series, series that makes you start watching new genres you never used to watch, are definitely real.

If you don't grow too passionate about the genre after watching a Gateway Series, after a few years you'll still end up with a vast knowledge about it and maybe a big pile of DVDs. If you do become passionate, then your room may be devoted to your new addiction. It all depends on how strongly you embrace your new tastes.

Someone's personal Gateway Series will be granted immunity from criticism thanks to the Nostalgia Filter.

Gateway series often have some things in common, mostly anything that causes a good first impression, both from the series and the entire genre. Each genre has a certain pattern, so to enjoy it you have to grow accustomed to those unique quirks. Thus, many Gateway Series blend styles or cross genres together; you are attracted to the series by quirks you already have and so get used to the new ones that way. Thus, Japanese Anime that has Western-style storytelling makes for good gates.

Maturity level also matters. In genres with age ghettos, a Gateway Series will likely double as What Do You Mean It's Not for Kids?? Or have many Parental Bonuses.

Deep, intricate storylines or massive loads of action are common, as well as being weird in a fun and upbeat way. Those things help you realize that this genre can have a lot of good and different stuff to offer.

Gateway Series must be good in some sense, and must not have much more squick than normally comes with the genre. Otherwise, you would be turned off.

Contrast It's Popular, Now It Sucks. Not to be confused with this or its video game adaptation. See also TV Tropes as a Gateway Drug.


 * The classifying of anything as being a 'gateway something' does not in any way imply that it is less good than the less accessible material it leads on to. All that we're saying is that for a lot of people, these examples lead on to discovering and enjoying other things. Its not a value judgement, just an observation of how fans tend to start from common points.

Anime
"One also has to recognize Sailor Moon's massive impact on American anime fandom. Hers was the first show that managed to draw in a measurable audience of real, live girls, who became genuinely hardcore fans thanks to shows like Rurouni Kenshin and Revolutionary Girl Utena. Which led, by a long and twisted trail, to a number of fanboys unexpectedly finding a way to lose their virginities at conventions some years down the line. They may not quite know it, but they owe you one, Sailor Moon."
 * Virtually anything aired on Toonami and/or Adult Swim has been a gateway anime for many viewers. Of course, Cartoon Network seems to have been pretty careful about selecting shows with mainstream appeal -- and clearly they've been successful. This makes it even more alarming that both daytime CN and Adult Swim have drastically decreased their amount of anime programming over the last year or two. Many have pointed at Cartoon Network's...controversial changes as the reason why.
 * And we're back.
 * Anime reached France en masse at the end of the 70s, and for a good part of the 80s, almost the most programs on children's television were anime. Also, due to Animation Age Ghetto syndrome, some totally non-suitable for kids series were broadcasted. It backfired spectacularly in the late 90s (until Cardcaptor Sakura then Pokémon made their way). Let's just list the biggest ones: Goldorak, Gigi, Albator (this one being extremely well-beloved. Did you wonder how Daft Punk knew Leiji Matsumoto?), Space Adventure Cobra (which main character was explicitly modeled after a French actor), Candy, Lady Oscar (there even was a movie by a famous French director), the furry version of Sherlock Holmes, Cat's Eye, Dragon Ball and Dragonball Z of course, Les Chevaliers du Zodiaque, Mahou Tenshi Creamy Mami (provided the Magical Girl page picture), Ken le Survivant (Sadly, not kidding. The dub deliberately Macekre-d and Gag Dubbed it to tone down the violence.), Juliette je t'aime, City Hunter, Max et Cie. And so on.
 * The Mysterious Cities of Gold and Ulysses 31 weren't seen as anime series, since they are french-japanese shows.
 * In short, French really LOVE anime and manga. Many series featured below in Latin America were broadcasted a little bit earlier or simultaneously in France.
 * Latin America had gateway anime quite sooner than the US, with series such as Mazinger Z, Saint Seiya, Space Pirate Captain Harlock, Space Adventure Cobra (!!!), Kotetsu Jeeg, Space Dragon Gaiking, Magnet Robot Gakeen, Candy Candy, Gatchaman, Astro Boy and many more being shown regularly after school and on the weekends.
 * Not to mention Rurouni Kenshin, Dragon Ball (and Dragonball Z), and Cyborg 009 among others like Pokémon/Digimon.
 * Those are quite new compared to the other mentioned. Dragonball and Pokemon were first shown around 1997-98, while Candy for example appeared around 1980.
 * Neon Genesis Evangelion. A lot of Otaku became interested in anime after they watched it. (On the other hand, it had the opposite effect on a lot of people too...)
 * One would think that the ways in which the series extensively plays with -- and brutally subverts -- anime tropes, the notoriously confusing plot, the highly divisive characters, and the all-around weirdness of the show would make it less than ideal viewing for someone unfamiliar with the medium. A whole new generation of Eva fans has arisen ever since the series was broadcast on -- you guessed it -- Adult Swim.
 * Actually Eva was first aired in the US by KTEH, a PBS affiliate in California uncensored in Japanese!
 * The pilot anime for Adult Swim was Cowboy Bebop, a series great for getting people interested in the medium.
 * One of the first well-dubbed series imported into the United States was Ranma 1/2.
 * Having a good dub helped, but the manga was a breakout hit too. Pretty much any Rumiko Takahashi series functions as a gateway series, thanks to her impeccable skills of characterization that transcend cultural boundaries. Just look at how many people in more recent years got hooked on anime after watching Inuyasha on Adult Swim.
 * The films of Studio Ghibli.
 * Not all shows like this have to be absolute masterpieces. Preteens who watched Pokémon in the late 90s went on to watch DBZ in their teen years and, in some cases, find themselves watching Adult Swim and beyond now.
 * Genres inside a medium do it too. Magical Girl Lyrical Nanoha, Kanon, The Melancholy Of Haruhi Suzumiya, Clannad, and AIR have converted many a shoujo fan to the Seinen series they once dismissed as fanservicey junk.
 * Akira is widely credited with introducing the anime feature film to the West in the late 1980s. Alas, Manga Entertainment capitalised on this by releasing a tide of unmitigated pap straight to video which left the general impression that all anime was Legend of the Overfiend and Violence Jack.
 * The tide of pap had some examples of its own, though. The Guyver: Bio Booster Armor, Ninja Scroll, the Street Fighter stuff, and Cyber City Oedo 808 all helped to get people interested in the medium.
 * As the owner of one of the major anime video companies once told a con audience concerned about bad dubs: "Sailor Moon is a gateway drug."
 * An early "gateway movie" for many early otaku was the Dirty Pair movie "Project Eden". Many came to it through Adam Warren's Amerimanga adaption of the characters, and it was frequently fansubbed.
 * Another early "wave" of anime fans came from Robotech, Star Blazers, or Voltron.
 * Battle of the Planets caused many fans to look into anime when they discovered, to their surprise, that the show they had enjoyed as a child was actually Japanese (and horribly edited).
 * Initial D is something of a Gateway Series for car guys to get into manga and anime.
 * The games too are like this. If you've never played arcade racers competitively before, Initial D Arcade Stage will help you break yourself in.
 * Kannazuki no Miko could be considered a Gateway Series, or an attempted one, for mixing robots and the standard young male robot pilot that could get the girl...but really leading into Seinen about Schoolgirl Lesbians.
 * It's the gateway yuri series.
 * Death Note was a gateway series for many into anime period, though for most it was a gateway series into a specific genre (not necessarily bound to anime either) containing darker themes, intense character interactions, strong dubbing, avoidance of the more obvious anime cliches and a decidedly anti-hero for a protagonist, leading many people to search for more "gray-area" genre series like the aforementioned Code Geass.
 * Trigun is another common gateway series, based on the mix of action and humor, and the particularly memorable characters. This, along with the aforementioned Cowboy Bebop was one of the first anime to premier on Adult Swim and one of the first to get a strong fanbase.
 * For several people, Aria is gateway series to Slice of Life anime.
 * For others, the gateway into this genre was Azumanga Daioh or Lucky Star.
 * Gundam Wing was one of the first anime to be shown on Cartoon Network that dealt with Real Life politics, in a stark contrast to the more fantastical and superpowered plots of Ronin Warriors and Dragonball Z. It was the success of the late night "uncut" showings that helped start Adult Swim. Unfortunately, Gundam Wing, while being the first Gundam to be officially introduced in North America, did not exactly whet American viewers' appetites for the classic Universal Century Gundam that came before it (Gundam Wing was only 5 years old and had strong animation so it at least felt like an original production. The 20+ year old Mobile Suit Gundam with the 70's look and shoestring budget clashed horribly with the cool/hip nature of Toonami. While some OAV's and movies aired on the network no other UC series got a chance.).
 * Both Gundam Wing and Gundam Seed, aired a few years after Wing, are generally acknowledged to be the two most recent gateway series into the Gundam universe, at least in the west. In Japan, on the other hand, the original Mobile Suit Gundam was popular enough to be a gateway in and of itself to the Universal Century.
 * Here is a quiz that can help you find your Gateway to the huge Gundam franchise.
 * GaoGaiGar (or Tengen Toppa Gurren Lagann for a more recent example) is an excellent way to introduce someone to the Super Robot/ Humongous Mecha genre.
 * For older anime fans Speed Racer and Star Blazers were gateway series in the 1960s and 1970s, respectively.
 * Naruto could be considered the the third Big Boom of modern anime watchers (the first being Dragon Ball and Toonami and the second being Adult Swim).
 * Also, Naruto and Bleach have introduced many anime fans into the Fan Sub industry.
 * Know someone who likes shows like CSI and Law and Order, and who thinks of anime as "kid's stuff"? Show them Ghost in the Shell: Stand Alone Complex. It seems to work quite well.
 * Similarly, the original Ghost in the Shell movie was one of the first anime to get attention from mainstream critics, and counter the stereotype that all anime was senseless sex and violence.
 * Nadia: The Secret of Blue Water managed to convert many Japanese proto-fans when it aired in 1990.
 * Sci-fi Channel's initial "Japanimation Week", back in the early 1990's, consisting of Robot Hunter Casshan, 8-Man After, Project A-ko: The Vs. Battles, Demon City Shinjuku, Lily C.A.T., Galaxy Express 999, and Robot Carnival stretched across the whole week. These and a few other movies subsequently went into the channel's "Saturday Anime" rotation. And let's not forget TBS' late-night showings of heavily edited Vampire Hunter D and Heavy Metal.
 * Ninja Scroll spawned a generation of anime fans.
 * Tengen Toppa Gurren Lagann.
 * To a lesser extent, Hamtaro.
 * Fullmetal Alchemist, which boasts good animation, fabulous story-telling, great characters and a pinch of dark themes. Both manga and anime are the kind of thing you'd introduce your friends to. Even those who don't even like anime love it.
 * Tenchi Muyo! or Love Hina as gateways to the Harem Genre.
 * You wouldn't think it, but stories abound of guys and gals who got into anime thanks to watching Rurouni Kenshin on Toonami.
 * Astro Boy could have been a gateway series, except there wasn't anything to come afterwards. Nonetheless, people who never watched another anime again know Astro.
 * Inverted with Eyeshield 21, where the series instead is a gateway to get anime nerds into football.
 * The Mysterious Cities of Gold.
 * Cardcaptor Sakura is considered by many to be one of the best magical girl series of all time, not only because of its own merits, but because it was a gateway series into the Magical Girl genre or anime itself.
 * Monster is set in Germany and drawn in an extremely realistic style which some people find atypical for manga and anime. It uses very few Japanese Media Tropes, favoring classic detective and crime tropes instead.
 * The Big O is heavily influenced by American fiction, having been called Batman with robots, so it's easy for Americans to follow. For a time Adult Swim showed it on weeknights just after Family Guy and Futurama, and it got a large enough following in the U.S. that they were able to finance a second season, showing new episodes at the front of their Sunday night lineup.
 * Sailor Moon. Best said here:


 * The first Yu-Gi-Oh series. A lot of younger tropers probably grew up with it before even knowing what anime was.
 * Heck, this is perhaps 4Kids' sole redeeming grace, via their dubs of the Pokemon and Yu-Gi-Oh anime. It helps that both franchises were wildly successful fads as well.
 * Over the years, The Castleof Cagliostro has been used by anime fans as a jumping-on point for the Lupin III franchise. This can get very ironic considering the titular character's actions and personality in the movie don't quite match up with any of his other incarnations.
 * Puella Magi Madoka Magica is the Gateway Series for the audience in The New Tens, its sheer popularity gets it noted people with intellectual creds. The problem is it's definitely not a good representation for its genre. But then, Evangelion wasn't a typical Humongous Mecha show...
 * Mariasama ga Miteru is probably the Girls Love gateway series.

Comic Books

 * Pick any comic book that has been adapted to Hollywood blockbuster format. Or, pick any comic book that has an Animated Adaptation you used to watch when you were a child. Familiarity plays a very important role here.
 * Or the other way around, a TV show that has been adapted into a comic book such as Buffy the Vampire Slayer.
 * The Sandman
 * Watchmen
 * Fables
 * Elf Quest
 * Maus
 * Persepolis
 * Preacher (Comic Book) to Vertigo Comic Books.

Film

 * Star Wars was a gateway to science fiction for many people when it first came out.
 * Crouching Tiger, Hidden Dragon was many people's gateway to Wuxia, or Asian cinema in general.
 * Rashomon was among of the first Asian films to gain critical acclaim or widespread release in the United States, and was many people's (including many future filmmakers) first introduction to Japanese (and indeed, Asian) filming and story techniques and the works of Akira Kurosawa.
 * Batman Begins set a standard of believability in Comic Book movies that eclipsed all previous attempts. This was successfully recreated in the Iron Man film and the standard was set once again with The Dark Knight.
 * Casablanca or Citizen Kane for classic films
 * Mystery Science Theater 3000 must have gotten plenty of people into B movies.
 * The 2007 Transformers movie got a lot of people into the franchise. It is currently enjoying success it hasn't had in nearly 25 years. The toys had original shipping numbers based on the previous line (Transformers Cybertron), only to find empty shelves for weeks while they scrambled to meet demands.
 * Beast Wars was a less-drastic but still notable example of the same thing. It goes to show that a good production will sell more toys than a movie designed to sell toys.
 * The myriad of Philip K. Dick adaptations (Scanner Darkly,Total Recall,Paycheck, Blade Runner, Minority Report) and also the William Gibson adaptation/basis of movies like Johnny Mnemonic or Strange Days as an introduction into sci-fi beyond laser beams and space ships.
 * While it was much less popular than Star Wars, and had much less of an effect overall, Children of Men apparently served as a gateway to science fiction. For some reason, it wasn't subjected to the Sci Fi Ghetto itself, and its lack of self-conscious "coolness" allowed it to stand as an example of science fiction in general rather than an example of cool action-style sci-fi like The Matrix or The Terminator.
 * The Scream series did a lot to introduce young people in The Nineties to all the older horror movies that it referenced/parodied, to the point where it's credited with singlehandedly reviving the genre after having been Deader Than Disco for the better part of the decade.
 * And decades before that, late night showings of old Universal Horror movies by TV stations did the same for the baby boomers. To an extent, they still serve as great gateways for younger or more squeamish viewers, since the Hays Code meant that the violence and sex was often minimal.

Literature

 * Harry Potter is a big gateway to fantasy novels, especially Urban Fantasy. According to Moral Guardians, it is also a gateway series to witchcraft, so watch out. It has also famously served as a gateway to books in general for people (children, teenagers and adults) who wouldn't normally read.
 * Lord of the Rings
 * Sandy Mitchell's Ciaphas Cain and Dan Abnett's Gaunt's Ghosts novels are good introductions to the Warhammer 40000 Universe; being not quite as Grimdark as the rest, but introducing the concepts and names via genre mixing.
 * Chronicles of Narnia
 * A Song of Ice and Fire
 * The Belgariad
 * The drug metaphor is doubly apt as it's own (now sadly deceased) author described it as "the literary equivalent of peddling dope."
 * While still a new series, The Hunger Games trilogy has been a gateway series for Dystopian Fiction.
 * The Wheel of Time was the gateway into the fantasy genre for a lot of nineties teens.
 * Twilight does serve as a Gateway Series for many young readers to Vampire Fiction or even reading in general.

Live Action TV

 * Doctor Who can be a gateway series for non-Brits to introduce them to British Telly, or British culture in general. They may then move on to Life On Mars or something similar. Generally anything shown on PBS stations.
 * Similarly, Downton Abbey might be to British Costume Drama what Doctor Who is to British Sci-Fi. Downton has become something of a surprise sleeper hit on American PBS stations. While Doctor Who might lead people to Being Human and Merlin, Downton might lead them to the new Upstairs, Downstairs and The Hour.
 * Stargate SG-1 is an excellent show for getting people into sci-fi shows, with it involving modern day soldiers in a variety of settings and starting off with more of an action feel, before going deeper into the sci-fi.
 * To a lesser extent, Stargate Universe has attracted people previously uninterested in the Stargate mythos to the franchise. Tycho of Penny Arcade wrote something to the effect of "I really didn't know much about Stargate other than that there are gates and they somehow involved stars but I like this show and am now interested."
 * Tokusou Sentai Dekaranger is a gateway series for those who entered Sentai fandom earlier than Gekiranger.
 * This is because Deka was the first Super Sentai series to be subbed in its entirety.
 * Your average western toku fan's story goes a little something like this: "Gee, I sure did like Mighty Morphin Power Rangers when I was little! So wait, it's actually an adaptation of a Japanese show? I think I'll check it out- wow, this sure is a good show!" And it goes on from there.
 * A popular gateway series to Kamen Rider is Kamen Rider Den-O. Only Decade and W are like Den-O so it's not especially representative of Kamen Rider.
 * Meanwhile, Kamen Rider V 3 can easily qualify as one to the various Showa-era series, due to being the only entry to get a legitimate R1 release.
 * If it weren't for Star Trek there probably wouldn't be half as many sci fi nerds as there are now. In fact, there probably wouldn't be as many people in the space industry.
 * Skins was also a gateway series to British Shows like Misfits and The Inbetweeners.
 * Iron Chef was a gateway series on two levels, one for the Cooking Show genre and two, for Japanese Game Shows in general.
 * Firefly can be this for those who don't know or didn't pay any attention to Joss Whedon, particularly those who were a little too young to be into Buffy the Vampire Slayer in its heyday.
 * Rescue911 has been this to Crime, Survival, and rescue shows. Not to mention, a couple people who watched the show in The Nineties were inspired in part by this show to become Police officers, firefighters, emergency dispatchers, and paramedics.
 * Babylon 5 seemed to attract a certain segment of viewers who weren't otherwise sci-fi fans.

Professional Wrestling

 * If you're a wrestling fan under 30, with very few exceptions, you started out watching WWF or WCW. As well, chances are you still watch WWE.

Music

 * With the help of YouTube, Straight No Chaser and their humorous renditon of "The 12 Days of Christmas" make a nice gateway into a cappella groups such as the Clef Hangers.
 * Not to mention Rockapella's appearances on Where in the World Is Carmen Sandiego?, probably the first exposure many had to a cappella groups in the 90s.
 * Since Woodstock and through much of the 80's, Sha Na Na occupied the same position as gateway group to a cappella singing, sharing it with The Manhattan Transfer. Which group was your gateway primarily depended on your age and whether your preferred musical style was doo-wop rock-and-roll or swing/jazz.
 * In the 60's and early 70's it was The Swingle Singers.
 * The music composed for shows such as Doctor Who or Battlestar Galactica can be a gateway for more classical music and famous composers.
 * For many, Daft Punk have been a gateway into the world of House Electronic music.
 * Similarly, Aphex Twin is one of the most well-known electronica artists in the world, and is often the first one people listen to before exploring others.
 * Green Day, Nirvana, AgainstMe! and NOFX are all punk bands who, though derided for going "mainstream" often act as Gateways to real underground and DIY punk rock.
 * Some of the more mainstream nu-metal bands like Linkin Park, Slipknot and Korn, while not particularly heavy, have served as good Gateways to much heavier and varied subgenres of the heavy metal musical umbrella.
 * And on that note, bands like Metallica, Megadeth, Slayer, Anthrax Black Sabbath, Judas Priest, Iron Maiden and Dream Theater tend to be common gateway bands into more obscure or specific subgenres of metal. A lot of people tend to get into metal through Alice in Chains, too.
 * System of a Down are a gateway band in metal, especially for people getting into death metal, noise metal, folk metal, and punk metal.
 * Some songs of Nightwish and Within Temptation making it into the pop music charts made and make some people interested in Symphonic Metal, if not Metal in general.
 * Pendulum is this for drum & bass.
 * The Prodigy brought an audience of alties in The Nineties to electronic dance music in general, thanks to being just harsh enough to appeal to them while maintaining their electronic roots.
 * Ace Combat Zero: The Belkan War's usage of Hispanic-styled music has led many to look into the style.
 * Enya serves a gateway to both Celtic music and New Age music
 * Nirvana, and to a lesser extent Pearl Jam, serve as a gateway to grunge at first, and then to alternative music in general. Sometimes this also leads to non-mainstream music of other genres in general.
 * Joy Division often serves as a gateway to all manner of 70s and 80s punk, post-punk and goth bands.
 * Pink Floyd could be this for Progressive Rock.
 * Red Hot Chili Peppers are a gateway into funk for many people.
 * Bob Marley&The Wailers are the usual gateway into reggae and dub. Also, they've covered many songs from the mento, calypso, soul, doo wop, funk and African genres which means that hearing the originals can often attract people to those genres as well.
 * The Clash are a gateway into many genres such as punk, rock and roll, reggae, dub, rap, dance and ambient.
 * Jamiroquai's early work in the acid jazz style is a gateway into latin jazz.
 * Many rap musicians who sample from groove and jazz records find this, Del Tha Funkee Homosapien, Grand Puba, Digable Planets and A Tribe Called Quest for instance all sample from Funk and Jazz records which often leads to people finding the origins of the samples.
 * Japan (the band) and their solo work are known for introducing people to piano music such as Erik Satie as well as Japanese music such as Yellow Magic Orchestra. Sylvian's solo work also is a gateway into the ambient and new age genres.
 * Outside of Japan, FLCL could be considered a gateway series for the music of The Pillows, and Japanese alternative and indie rock music as a whole.
 * Due to the band's brief American pop radio success in the mid-2000's, Modest Mouse were a gateway band into the world of indie rock for many future fans of the genre.
 * For listeners who don't remember the 1960s (for reasons other than drugs), The Beatles can function as a gateway band for music of that decade and "oldies" in general.
 * Any time a song is used in a movie/TV show/game/etc., it gets people into that song or band.
 * Mumford & Sons is a gateway to the British Folk genre, and in turn indie music. Coldplay can also be considered a gateway into indie music.
 * Perhaps the best example of the last DECADE is Kids by MGMT. Without that, songs like 1901 by Phoenix and Pumped Up Kicks by Foster The People would not become popular. Both this and the above example of Mumford led to Adele having a worldwide smash and Gotye's Somebody That I Used To Know hitting number one for weeks and weeks.

New Media

 * Look no further than the very website which you happen to be browsing at this (probably) late hour. How many books, TV shows, etc. were you blissfully unaware of before coming here but now have a sudden unrequited urge to experience?
 * Youtube Poop introduces many younger people who weren't able to watch them when they first aired to cartoon adaptations of popular video games such as Adventures of Sonic The Hedgehog, to the Philips CD-i as well as Volvic mineral water, Team Fortress 2 and since the rise of the #71519 fad to The Critic.
 * AMVs and fanvids in general.
 * The Spoony One, and his review of Final Fantasy VIII in particular, introduced a lot of people who came in late to internet reviewers, and specifically the critics on That Guy With The Glasses. (Given the amount the reviewers cameo in each other's videos, someone who starts with one will soon be aware of most of the main cast.)

Radio

 * The hobby of shortwave listening can eventually lead to the hobby of ham radio operating. It can work the other way around, too.

Software

 * Mandriva Linux and Ubuntu are meant to be easy-to-set-up, easy-to-use gateways into the world of Linux, as reflected in Ubuntu's slogan, "Linux for human beings", and with people often switching to more complex distros such as Red Hat, Fedora or openSUSE, and some of them later graduating to technical distros such as Debian, Gentoo, Slackware, Arch, or even leaving Linux and switching to BSD or OpenSolaris.

Tabletop Games

 * Dungeons and Dragons Fourth Edition in particular has been rather successful at being friendly to new players.
 * New editions of D&D in general seem to do this. Much the same thing happened when 3rd Edition came out, and the gaming scene in general saw a big boost in the wake of the open-content d20 System.
 * With a few exceptions; Jonny-Come-Latelies joining at the height of 3.5 (Or now since 4th edition groups are rather rare) would probably find themselves swarmed with dozens upon dozens (if not even a hundred or more) of the various kinds of books, including but not limited to the player's handbook, monster manual, magical items, expansion books, class-detail books (Like Complete Divine), update books, and more.
 * Has also been used negatively by gamers in reference to D&D. Some gamers, for instance, feel that D&D is a shallower and less "worthy" part of the tabletop gaming industry and that it's so popular only because it's so easy to get into.
 * Vampire: The Masquerade of the Old World of Darkness has been a more recent gateway game.
 * Particularly its simplicity compared to D&D and its modern horror setting has meant that its attractive to a lot of people who otherwise might not be interested in role playing. It also is pretty much focused on letting the players be anti-heros (or outright bad guys) which is definitely more attractive to the angsty teens.
 * Warhammer 40,000 is often a gateway to Tabletop Games as a whole. You start with 40k after coming across it as a teen, then after a few years you might move along and start playing spin-off game or even Warhammer Fantasy. If you play at a multi-gaming club, you'll probably end up at the very least being interested in those systems as well and there's no telling just how many you might get into.
 * Board games such as HeroQuest, or the Fighting Fantasy and Lone Wolf books often serve as a gateway to Tabletop RPG gaming.
 * Tunnels And Trolls was explicitly designed as a simpler, easier-to-play clone of D&D, in an attempt to bring in new gamers. It never did achieve the popularity of D&D, but there is a sizable group of tabletop gamers that cut their teeth on T&T.
 * Western Computer RPGs
 * The Choose Your Own Adventure and Fighting Fantasy books were a gateway for many roleplayers of the 80s.
 * The Pokémon and Yu-Gi-Oh! card game led eventually to Magic: The Gathering for lots of players. Helped by the fact that a lot of sanctioned tournaments of the former shared venues with tournaments for the latter. Also, the huge media presence (straddling many years) and child-friendly image of both Pokémon and Yu-Gi-Oh practically guarantees that these will be the first CC Gs people get into.
 * And, in turn, a number of Magic pros who become accustomed to making high-stakes probabilistic decisions end up transitioning to poker (most notably David Williams).
 * The Dark Eye is the Gateway system in German-speaking countries, despite beeing the deepest system around.

Theater

 * Rent, Les Misérables, Avenue Q, and Wicked for musicals.
 * Cirque Du Soleil's various shows have introduced a lot of people to the contemporary circus genre.

Video Games

 * After The Great Video Game Crash of 1983, people thought gaming was dead... but then enters Super Mario Bros. bundled with the NES...
 * Related to it, practically everyone got into Platform Games due to Mario and Sonic the Hedgehog.
 * For PC gamers, Commander Keen or Jill of the Jungle is likely to take this role.
 * Final Fantasy VII was a gateway RPG for a lot of players -- to the detriment of the genre, some might argue. And it doubled as a bit of a gateway introduction to anime as well.
 * It was also a gateway to PlayStation games in general.
 * The Final Fantasy series as a whole can be considered a gateway to RPGs.
 * Super Mario RPG is a a very good introductory RPG that's actually an RPG.
 * The Baldur's Gate series.
 * The Elder Scrolls.
 * Not only can Pokémon count as a gateway to anime, it's also a gateway to the Mons genre and to some extent to RPGs in general.
 * Many games designed by Nintendo for the DS and Wii were intended to be gateway videogames for people who never tried them before -- like Wii Sports, Nintendogs, Elite Beat Agents, and so on.
 * Nintendo has the reputation of being the video game company that makes games to introduce people to videogames who never played them before, something that the company opens states being their goal. Of couse, some people don't say it like that.
 * In fact, let's just say Casual Games in general, though there can also be Gateway Games for certain types of Casual Games as well (e.g. Diner Dash for time management games).
 * The Tony Hawk games are a two-way gateway -- they've gotten a lot of skaters into gaming, but it's when they get gamers into skateboarding that Hilarity Ensues.
 * The Super Smash Bros. series has a wide variety of Nintendo characters, and some players might become more interested in the individual series if they see a character they'd never heard of before. The appearance of Marth and Roy in Melee for example, led to the introduction of the Fire Emblem series to the US.
 * Brawl even has demos of several of the characters' starring games.
 * A variation of this trope: a lot of people become regular readers of Game FAQs after getting stuck in Guide Dang It moments.
 * Long-time series such as Castlevania -- espeically Symphony of the Night tend to be gateways for modern players into the world of retro gaming, especially those curious about references to characters from previous games.
 * "People who don't like video games like Myst."
 * World of Warcraft is the most infamously addictive MMORPG out there nowadays, but those who have played it and quit often try to seek out other MMO's afterward.
 * Halo for Multi-player FPS. (Arguably before then, it was Doom) Being a launch title for the Xbox, many gamers who did not play FPSs before played it. It's argued that Halo was the killer app that allowed the Xbox to compete in its early days against the wildly successful Playstation 2. So that's gotta count for something.
 * Half Life and Counter-Strike would like to contest this claim as well.
 * Thief, a stealth simulator, was marketed as a big new twist on the overinflated First-Person Shooter genre. It got quite a few action gamers interested in stealth games.
 * Metal Gear Solid served an almost identical function to Thief on an entirely different system. Also, due to its slow-paced gameplay, its focus on storytelling and the ability of the player to pause the action to talk to the other characters about trivial things, it also makes a great gateway series for people raised on JRPGs trying to break into Action Games.
 * If you stick around the Dance Dance Revolution community long enough, you may come to try out other Rhythm Games -- up until the release of Guitar Hero, this would be things like Beatmania IIDX and Dance ManiaX.
 * Although for a lot of people it now works the other way around, with Guitar Hero or Rock Band being the gateway game that leads them to discover Dance Dance Revolution.
 * This can also work across media -- Guitar Hero and Rock Band inspire people to buy and get into music from the games.
 * These two games can also turn people on to real instruments. Hilarity Ensues when they realize a real guitar's nothing like the plastic controller.
 * Of course, neither of these games would have been possible if Parappa the Rapper hadn't opened up the world of rhythm gaming to start.
 * Street Fighter does this for 2D fighting games. The series is relatively user friendly and easy to pick up and play, leading many in more complicated games like Guilty Gear.
 * Similarly, Dead or Alive does this for 3D fighting games due to its simplistic controls and large appeal.
 * Play one addictive puzzle game, and you're bound to wind up hunting for more. Peggle is a good example.
 * Tetris for older tropers.
 * Many gamers' first Real Time Strategy game was Warcraft II, and for good reason, too. The graphics are nice to look at, the mechanics are fairly simple compared to other RTS games, and most importantly, it's a lot of fun (including against your friends, even if they do kick your butt in 95% of the games you play with them).
 * If your first RTS wasn't Warcraft II, then it was probably Starcraft.
 * Or you may predate Warcraft II and have actually played Warcraft: Orcs & Humans for your first RTS.
 * Someone forgot Command & Conquer -- Tiberian Dawn and Red Alert
 * Command & Conquer? You forgot Dune II.
 * Dune II may have started the genre, but it certainly was no Gateway Series. Warcraft II was indeed the first game of the genre that became mainstream (though, as mentioned above, those who missed it simply found Starcraft first).
 * All these games can be considered Gateway Series depending on your age. Westwood Studio games like Dune II and the Command & Conquer series were extremely popular at the time. Blizzard Entertainment only became a clear leader when they released Starcraft.
 * The Super Robot Wars series can potentially be a good Gateway Series for many Giant Robot Anime, considering that the plot for each game basically takes the plot of every series involved in the Massive Multiplayer Crossover and shoves them all together.
 * Nintendo games almost always serve this trope, but this console generation aiming for this has basically become their entire marketing strategy. The self-proclaimed "hardcore" gamers may lament that women and old people are getting in on their hobby, but it's hard to fault Nintendo when they're clearly getting results -- games and systems, Nintendo and otherwise, are selling better than they ever have even in the economic recession.
 * The Humongous Entertainment games were designed to be like this.
 * Although Rogue was, by definition, the first Roguelike, many fans of the genre get their start with the Trope Codifier, Nethack, leading into more difficult games like Angband, and a greater acceptance for ASCII games in general. It's probably not a stretch to say that Dwarf Fortress wouldn't exist if it weren't for Nethack.
 * It's kind of a stretch; Dwarf Fortress is only an ASCII game as a temporary convenience. If it weren't for exposure of Roguelikes, toady probably would have spent a lot of his development time struggling with a GUI.
 * Powder and Shiren the Wanderer are good gateway roguelikes for those discouraged by the complexity (and ASCII-ness) of Nethack and company.
 * Touhou has introduced many a gamer to the wonderful world of Bullet Hell shmups.
 * For some people, DoDonPachi, Batsgun or Battle Garegga, especially if they play arcade games a lot.
 * Although two games predate it (in America, at least), Tales of Symphonia was the Gateway Series to Tales (series) for a lot of Western fans. It being one of the better RPGs on the GameCube meant that it drew a lot of attention from people who had previously dismissed the previous games in the series. Also, Tales of the Abyss to an extent, purely because it was for the PS2.
 * Quite a few people have been introduced to either the First-Person Shooter genre, PC gaming, or both by way of Team Fortress 2.
 * Sakevisual, the artist of RE: Alistair, wants her game to become a gateway series for fans who don't yet know about otome games.
 * Interactive Fiction started the Adventure Game genre, but many felt it to be too inaccessible. The move to graphic adventures was fairly rapid, but despite some awesome games like King's Quest and Maniac Mansion they remained a niche genre for several years. Then Lucas Arts (at the time still a strict part of Lucasfilm) went and made a game called Loom, one of the most accessible adventure games ever created. This created a veritable explosion in the PC adventure game market, which ended almost a decade later. And for those who were not yet fully convinced, Lucas Arts followed the left punch with the right soon thereafter, giving us the most famous PC Adventure Game ever created, The Secret of Monkey Island.
 * Persona 3 and Persona 4 are good start for those interested in the Shin Megami Tensei series, seeing how they're generally considered the most accessible of SMT games. In fact, the original Persona was designed to be a more easier SMT.
 * The Sims, with its broad market appeal, was many people's gateway to videogaming in general.
 * Poker Night At the Inventory got a lot of Team Fortress 2 fans into Sam and Max Freelance Police and Penny Arcade.

Visual Novels

 * A main gateway series to Visual Novels is arguably Tsukihime, and in a broader sense, the Melty Blood fighting game series. While some eroge can surely bring with them a great story and be classified as Porn with Plot, it usually isn't marketed or seen that way in the West. Many a Visual Novel has been consumed since then, and since something as broad as Visual Novels is rather variated, rather guiding newcomers to Planetarian, and from there:
 * Those that may be averse to 18+ material to Ever 17 or Kira Kira (the all ages version)
 * Those with a unique taste to anything by Looseboy, Urobuchi Gen, Kinoko Nasu, or Romeo Tanaka
 * And those looking for gameplay or humor (or both) to Galaxy Angel, the Ace Attorney series or Sengoku Rance.
 * Kichikuou Rance was a Gateway Series in its native Japan since it is one of the highest selling H Games of all time.
 * Katawa Shoujo is one partly because it is English Language Freeware, partly because its relation to 4chan and its concept as a Disabled Love Interest H-game made it somewhat famous, and partly because it is well made.
 * Katawa Shoujo is such a Gateway Series that it made the front page of Game FAQs as the top of the list of 10 Most Wanted Faqs.

Webcomics

 * In 2000, Penny Arcade linked a new webcomic they found, which caused Megatokyo to have an almost instant fanbase.
 * Penny Arcade in general is a Gateway Drug, since many of the things that Tycho links to in his blog end up getting hit by a surge of readers/viewers. This happened with both Doctor Horrible and Minecraft.

Western Animation

 * Disney Animation, and perhaps Looney Tunes serve as a gateway into the widely varied world of animation.
 * Batman: The Animated Series serves as an introduction into the DCAU, and to the overall Batman mythos.
 * As with the film adaptations, animated TV adaptations of comic books often introduce many people to the characters and the setting.