Ouran High School Host Club/WMG

Kyoya's constant laptop use..
is him sorting out and arranging, and so whenever we see him typing on his laptop, and rarely if ever working for ths host club he is in fact

Haruhi is... Kyon
And Tamaki is Haruhi. It's a Gender Flipped wacky alternate universe, where Suzumiya is a boy and, while not aware of his powers, using them more actively. The other club members are the other factions.
 * Kyoya is the Data Entity agent.
 * Hikaru and Kaoru are espers.
 * Hani and/or Mori are Time Travellers.

Tamaki is Obfuscating Stupidity
He is playing the family charade as Kaoru suspected, but he denies it because no-one else would suspect it.
 * Also, in connection to the Kyoya WMG, he is aware of it and deliberately sets up a Bumbling Dad scenario, where Kyoya can act as the Closer to Earth mother figure.

The two above statements are both true.
They are a couple of twins, but not necessarily a romantic couple. They are tricksters, after all. Twincest-playing tricksters.

One of the Hitachiin twins is straight, and one is gay.
Considering the issues with Haruhi, Kaoru's probably the one being serious about the Twincest; Hikaru just goes along with it because he likes getting attention, messing with people, and placating his brother - who does ship the two of them. Also, it should make the Twincest/HoYay fans, the Hitachiin x Haruhi fans, and the Twincest-playing trickster fans happy, or at least not discontent.
 * In the manga, Kaoru is canonically in love with Haruhi as well, and the twins get into a bit of a dispute over it (a real one... mostly). Although, it does seem very like that Hikaru is bi, as some form of he has love for Tamaki further complicates his feelings for Haruhi. Its never blatantly stated that its romantic love, but its difficult, for me at least, to not interpret it as such.

Kyoya is in love with Tamaki
Kyoya is highly cynical; before meeting Tamaki, all social mingling was only to gain influence. Tamaki defied his conceptions, and his Wide-Eyed Idealist attitude genuinely shocked him. His love may or may not be the romantic sort, but they certainly do act like a married couple at times.
 * Kyouya is one hell of a Tsundere.
 * Kaoru in fact specifically calls Kyouya a Tsundere with regards to Tamaki in volume 11 of the manga.
 * In episode 24, when Kyoya is asked why he joined the host club, he looks across to Tamaki, who is bathed in white light, and then smiles to himself before answering.
 * There's also episode 3, where Kyoya states that he doesn't think he's "supporting cast, homosexual or otherwise."
 * Basically, Kyoya being in love with Tamaki explains all of the the abnormal behavior around him, as well as how Kyoya is 'only' really close with Tamaki.
 * Also, from the manga, Hikaru, Kaoru, Tamaki are shown developing a bond with Haruhi, Mori & Hani act as supporters for everyone. Who makes Kyouya spend his entire school trip in  and who's the only person who makes Kyouya lose his cool, and who's the only person that made him outright scream at Yuzuru Suoh  which was against his wishes, resulting in Kyouya needing to be RESTRAINED? Tamaki.
 * Or he's not and he's just very close with the first friend he ever had and doesn't want to lose him. Until Tamaki, Kyouya didn't have friends, and people like Tamaki are hard to come by.

Honey has the same illness as Kanata (and possibly Konata) from Lucky Star
Much too small for his age? Check. Strange behaviour? Check. Great intelligence? Check. He's going to die young.
 * So, he'll need a fujoshi childhood friend to make sure his heirs will come to the world... And then, when she's 40-something, she'll chase after young boys that remind her of him... Or not necessarily. Just like Konata's dad.

Haruhi doesn't have Haruhi powers, but Hani does.
He (or at least Mori) thinks it's funny for Tamaki to be the Butt Monkey of the series, which is why he's always so incredibly Wrong Genre Savvy. Hani fulfills the shota role in the club, but can still out-fight any other person in the club, probably at the same time. He always looked young, but hated having to stay either strong or cheerful-happy-cute, and subconsciously limits his size while allowing himself a ridiculous amount of physical power. The rest of the club (apart from Haruhi and Tamaki) know about his power, and the teachers are probably in it too, the real reason they let him keep Usa-chan with him whenever he wants.

Honey's bunny is evil
All stuffed animals are.
 * No, you are, meanieface ;_;
 * Re-watch some of the episodes. I've seen some rather... questionable... facial expressions on that bunny. I'm watchin' you, Usa-chan.

In addition to the above guess, Usa-chan and Beary represent Hani and Mori.
Usa-chan and Hani are cute and cuddly, and like to eat cake. However, they both have a much darker side, which rarely manifests when others are watching. For Usa-chan, the exception is when only the audience is watching, for Hani the exception is when he's just woken up. Beary, Tamaki's plush bear, has a similar expression to Mori, but Mori wouldn't have a stuffed animal, so it was necessary to introduce him via another character. (Since Hani only shows Dark Hunny when he's just woken up, and Mori only gets all creepily pleasant and smiley when he's sleepy, this means Beary only has a smile when the audience isn't looking in comparison to Usa-chan. This unfortunately means that the theory is impossible to confirm entirely.)

Honey is psychologically unhinged
The guy's 17, yet he still takes naps and thinks Usa-chan is alive. If his dad hadn't been so hard on him, he would probably have become a fairly well-balanced martial arts master who happened to be fond of cake and teddies. However, his dad forced him to be all tough and manly, which rather went against his sweet nature. Tamaki later offered him a chance to indulge in the things he truly likes, which led to him swinging too far in the opposite direction and mentally regressing to the age of 5 or so.
 * What's wrong with taking naps? You got something against naps?
 * I could be wrong, but it's all developmental. The kid still has his "security blanket" in the stuffed rabbit, still needs an "older brother" figure to cart him everywhere, and naps? Unless you're really tired, how often do you take naps in the real world? At seventeen most of us were getting ready to head out into the real world and get ready for life, but this kid was still acting like a kindergartener.
 * Please, I'm barely 18 and I take naps most days. It mostly springs from me staying up really late, like most high schoolers. Plus, mid day naps are fairly common place in some places.
 * Forget the naps, Honey still acting like a child, and as the manga shows, takes pills to keep him looking like a child shows perhaps he has unresolved issues...
 * The pills were only in a dream sequence.

Honey still practices martial arts in secret, either alone or with Mori
No matter how well-trained or naturally talented he is, he'd need to keep sharp in order to beat up the Ohtori private police on two occasions. The exercise allows him to eat all that cake without gaining any weight.
 * Mori is shown to still practice every now and then, presumably, so does Hani, it just is never shown.
 * In the manga, he still practices every day, he just doesn't attend Karate Club except every so often as an outside instructor.

Hani is Obfuscating Stupidity.
His Superpowered Serious Side is what he's really like. He likes Mori but knows he'd feel useless without having shota-kid Honey to protect, and also enjoys being able to fill a niche in the Host club, and still gets plenty of attention while eating cake and having fun. (Note: In the Beach Episode, Tamaki as much as pointed it out to Haruhi.) Usa-chan is just there to reinforce the image.
 * That means each member of the host club is hiding their true selves because of social restrictions or past experiences, and it's Haruhi that finally unlocks all of their emotions by the very end of the series.
 * This (the first response) is seemingly the canon story path of the manga, with the "walls" references. (Original poster here) The guess was meant to apply to the anime, but it works for both.

Haruhi is biologically male.
That is to say, she's a gynandromorph or hermaphrodite, who identifies herself as a woman, but doesn't care how she dresses. Ranka knows this and honors her belief. It will be revealed at the end of the series.
 * Problem is she isn't all flat. In episode 22 of the anime Kasanoda accidentally sees her changing and she obviously has some chest. Now there's a possibility that she's a he in other areas, but that would mean 'it' was changed in their upper regions in their early teens.
 * Can't say much about gynandromorphs, but hermaphrodites usually do have breasts.

Haruhi is Lelouch.
Her "contact incident" in episode 4 was really her about to unleash her Geass on the unwitting Host Club.

Haruhi and Tamaki died when they fell into the water in Episode 26 of the anime
Think about it. They seem to be a good distance up, and while they may be okay swimmers, well... why else would Eclair let go of Tamaki? Methinks she just thought "May as well let him die with her." That's why the car drives away and such. What we see with Eclair afterwards is in the actual aftermath in the real world. The final waltz is a Dying Dream of sorts.
 * ...Okay, this very firmly falls into Poison Oak Epileptic Trees.

Eclair had feelings for Tamaki
Just look at this screenshot. You can't deny the puppy dog face. You can't.
 * ... that really, really doesn't count as a WMG.

Hikaru and Kaoru are a reference to Castor and Pollux
Hikaru means "shining". Kaoru means "sweet smelling". Castor means "shining". Pollux means "very sweet". Coincidence? I think not.
 * Castor means "beaver". What's your source on the alternate translation?

Honey's Usa-Chan and Iori's Usa-chan are one and the same
Now, how this works can be chalked up to time-travel(See top of list), one being the other's parent, or Honey and Iori are the same person, just one is the result of gender-flipping.
 * Darry's Usa-chan is a zombie version, it seems.
 * Well, you couldn't expect him to live forever, could you? He probably decided to become a zombie so he could continue watching over members of the bloodline even After the End.

Haruhi is going to punch out Tamaki's grandmother
His grandmother is going to do or say something especially despicable in front of Tamaki in front of everyone, and Tamaki won't do anything about it for the usual reasons. Haruhi, still confused about her feelings towards Tamaki and needing and outlet for her emotions, will punch the grandmother right in the face. It will have repercussions later, but it will be awesome.
 * I think Haruhi is more likely to deliver a verbal Curb Stomp by saying something so devastingly insightful and far more damaging than any mere punch in the nose. It will still be awesome.
 * And the way it will be awesome? These devastatingly insightful words will turn into giant, colorful arrows that will proceed to pierce Tamaki's grandmother from various directions, culminating in a giant lightning bolt falling from the sky and frying the old bag, who will then fall backwards in slow motion (possibly with Beartrap mouth,) much like with Renge and Tamaki himself back in season 1 of the anime.

Tamaki Really is Haruhi's Real Father
Through CLAMP-like time paradoxes, later in the series, it will be revealed that Haruhi really is Tamaki's son... and also her own mother.

Renge is more of a parody than people think
She's not just the yaoi fangirl with a loose grip on reality that she seems to be; she's actually a parody on the fanbase itself. Her "film project" that rewrites all the characters is an alternate universe fanfic. Every facet of her is seemingly designed to parrot that of the yaoi fangirl base, which is probably why the fangirls seem to lash out at her so much; she is them, and they don't want to admit it.
 * There's also a scene in the manga that supports this further. When the Host Club put on a bunch of activities, one of the activities was to guess which Hitachiin twin is (something that hadn't done in a real long time at that point). Renge is convinced that she knows everything about the characters to guess which is which easily, however she's repeatedly wrong. Much like how those extreme fans believe that they know so much about the characters of a fandom, that they know more than the creato; they'll disregard any evidence that isn't according to what they believe to be canon. Expect outrage when the creators doesn't go according to their personal desires, and start making everyone "OOC" when the creator is actually making the characters behave normally.

The universe in Ouran is the same as that in SOUL EATER.
In addition to sharing the same animation studio, same director, and a few of the same voice actors, there are in-universe implication. The characters obviously live in a world equivalent to modern Japan and other parts of the world- and who's to say the characters in SOUL EATER are not sent on missions in the same world?

Taken further, Spirit Albarn (or Death Scythe) is adult Tamaki.
Tamaki graduated from school, became successful, married, had Maka, and then divorced. He then went a little bat-shit insane after the break-up, became somewhat of a ladies' man, and changed his hair color. In English, they're both voiced by Vic Mignogna. ...that wouldn't explain the different last names, though.

Beary is just a nickname.
Its real name is Ursa-chan.

Haruhi is Suzumiya Haruhi, who wanted to try being male.
But not too male, so she settled for being a crossdresser.

&Atilde;‰clair Tonnerre's binoculars stood for her bitchiness.
In the last episode, she seemed to accept the fact that Tamaki wouldn't marry her and dropped her bitchnoculars and seemingly, her bitchiness.

Haruhi likes the girls too.
She likes being part of the host club cause of the female attention. Girls that would never lust after her if they knew that Haruhi was female are. And Haruhi taking advantage of that fact. Parents can be a huge influence on what is normal behavior, and Haruhi's dad is well...a cross dressing bisexual. Plus, Haruhi didn't seem to mind the fact that her first kiss was from a girl.
 * Actually, Haruhi herself points out in the first chapter that gender and appearance aren't really that important, but that it's what's on the inside that truly makes a person. Plus, the very end of the first chapter has Haruhi saying this after Tamaki finds out she's a girl: "And actually, I realized it's not that bad to be popular among the girls. They are cute. I'm probably a little into that..." Whether she seriously meant it is speculation, but she does look contemplative in the panel.
 * The intro song on the English dub seems to refer to this, with a line that goes something like "Lady maybe. Or host, I find I really don't mind." Then the next line refers to her finding love in a garden of romance.

One of the Hitachiins has a pigtail Fetish

 * Think about it... every time they've dressed as girls, they've had their hair in pigtails
 * And Haruhi wore pigtails on their date

Kyoya's notebook is a Death Note

 * Really, I'm surprised no one else has thought of this.
 * On top of that, he's actually Mikami.
 * And in the last episode, he stays with Hunny and Mori to fight the police force, even though he (probably) has never had extensive martial arts training like the other two -- then at the end of the fight all the bodies are piled up, so we assume Kyoya helped in SOME way...probably by using his Death Note.

Tamaki and Haruhi are the reincarnations of Edward and Winry respectively.

 * Basically, since, Edward and Winry never got to be together, so they've been reborn into a world where they can finally have their happy ending...and as an added bonus, Ed gets to be tall!
 * Roy gets to enjoy a life with his apparently best friend Wrath. Shou Tucker is still a doctor that misses his daughter, though he's much less crazy about it. Rose (or is it Riza) is now a rich french lady. Dante got redeemed and transformed into a chaotic fangirl. Also, Al got a pretty raw deal by becoming a short kid's younger brother again.
 * Jossed by the fact that Ed canonically lives to be at least 100.
 * Exactly (and it's Riza)!

Renge-kun convinces the Host Club to produce a full-length television series, which they call Supernatural.
Like a real-life Mori and Hani, Jensen and Jared are lighthearted dudes who constantly make with the angst and woe on camera so the ladies will swoon. As themselves, they try to always be charming and dashing, with great success.

Haruhi is richer then Tamaki or Kyoya because her father actually loves her.

 * Awwwwww!

Haruhi is richer than Tamaki or Kyoya, but her father actually loves her.
It builds character to not know that your mother was the richest person in Japan until the age of eighteen, and left an enormous fortune apiece to you and your father, possibly in agreement that you should be spared the distress later in life of being spoilt. Plus, commoners' coffee is amazing! You can pour it right into the hot water!

Tamaki's Grandmother once had a relationship with a pre-movie Prince Naveen.

 * Grandmother Suoh hates her grandson Tamaki, but not just because he's the result of her son's defiance in marrying a French woman that he chose for himself; his cheerful and suave personality reminds her of a young prince that stole and broke her heart when she was a young woman in the 1920's.

Ouran Acadamy is a school for Twilight style vampires. Haruhi was admitted to be eventual prey before Tamaki took a liking to her.

 * Everyone in the school sparkles and withstands an incredible amount of slapstick physical punishment. The families are not truly families but vampire covens who have amassed wealth and influence across Japan over the centuries. Everything we hear about Hani's fighting ability is the absolute truth due to his skill combined with enhanced vampire powers. The Occult club is actually made up of vampires who have regressed into older vampire sub-races that are weakened by direct sunlight. The Lobelia Academy is actually a school full of potential slayers who are trying to save Haruhi from the vampires.

Haruhi is the little girl in the twins' flashbacks.

 * Both Haruhi and the unknown little girl had long brown hair. The little girl's face is never shown, something that would usually indicate a secret, surprise character that would be revealed later. At that age she can't tell the twins apart, but she's one of the few people who seems to realize that they're separate individuals. Haruhi's mother would still be alive at that point, and with a lawyer's salary and maybe a bit of financial aid, Haruhi could very well have attended the same school as the Hitachiins.
 * Haruhi doesn't remember being in preschool/kindergarten with the twins, but they remember her. She stands out in their flashbacks as someone who actually realized they were different people and not just two identical parts of a matched set. This probably has a lot to do with their current feelings toward her.
 * Impossible sadly due to the twins being in a different social class to Haruhi and so probally being in a very posh private school, maybe the elementary school to the middle and high school Ouran.

The clipboard Kyouya always writes on is the Death Note.

 * C'mon, you thought it as well.

Ouran is really the clash of two rival breeding programs

 * Hani is a doomsday weapon and Mori was created to handle him that why we never see Hani without Mori. The twins were created for psychological war fair, send them to your enemies and watch them suffer. Kyouya is for financial take over and logistics. Tamaki was supposed to be a political leader, he has enough charisma but his since his mother was not part of the program, he ended up French. Haruhi was created to uncover this elite breeding program, the commoner created her with their ultimate weapon: common sense. then she was sent to infiltrate

Renge is Aphrodite

 * Aphrodite did something to anger Zeus and got sent to Earth with her powers revoked and memory locked away as punishment. She finds solace in dating sims and managing the Host Club.
 * That's also how she can speak fluent Japanese and French both.

Haruhi is the Rose Bride
In the not too distant future Ohtori Academy changed it's name to Ouran. All of the various characters who compete for Haruhi's affections are really trying to gain the "Power to Revolutionize the World". Tamaki wants the power so he can keep the "family" he built within the Host Club together forever. The twins want it so they can create a miracle where someone will finally be able to tell them apart. Honey wants to find "True Strength". Mori wants to help him. The Lobelia girls want to prove their superiority over men. Kasanoda wants control over how the world views him, and Renge wants the world to be perfect and ideal like her Dating Sim games. Kyouya is End of the World.
 * Does that mean that Kyouya and Haruhi...

Mizuho is Haruhi's dad
He really couldn't resist!

Kyouya's father is abusive
At least in the anime. Yoshio is definitely emotionally abusive/neglectful, and sometimes seems to think of his son as nothing more than another tool to make connections. Sure, he implied he was proud of Kyouya like once, but he's never said a thing to Kyouya himself, which has/will lead to Kyouya having some serious issues. He's probably physically abusive as well, because he clearly cares a lot about his public image, and yet had no problem with smacking Kyouya so hard that his glasses flew off of his face. If Yoshio thought he could get away with doing this in public (though he DID apologize for making a scene), just what's going on back at home? And remember that when Kyouya walked away from his friends, he shrugged off their concerns with a statement something like "I expected that to happen anyway," so it's obvious that this is far from the first time Yoshio has hurt him. ....I made myself sad.
 * It's also why Kyouya never allowed himself to make any real friends before Tamaki; he used people as little more than connections not because he wanted to, but because he was too afraid not to do exactly what his father says.
 * Jossed in the manga where Kyouya's father never actually hit him, and instead congratulated his son for his involvment in the Host Club (he thought it was a clever business move).

Everyone knows that Haruhi is a girl.
Tamaki is the only person established as being THAT stupid. Every member of the host club figured it out almost immediately. All the female customers are probably just playing along because they like her as a person. I can see Bisco making the reveal the no secret.
 * Also, Haruhi is a girl's name. Someone would have mentioned by now that it's an odd name for a boy if they weren't in the know.
 * IIRC, Haruhi is a unisex name that just happens to be more common as a girl name (much like "Kelsey" in America,) so it might not seem so odd for a boy to have that name.
 * In the manga, all the customers discovered at the end. They didn't know, but the boys thought that they did know.

Renge will end up with one of the hosts.
It would be after some MAJOR character development on her part, but come on, Rule of Funny.

Tamaki is the Anti-Lelouch, and by extention, Ouran is a Bizarro-Ashford Academy
Not only does he look like a blond Lelouch (or is it vice-versa?), but...
 * Tamaki is obsessed with Haruhi, while Lelouch is Asexual (or at least much more reserved).
 * Lelouch is on the Absurdly Powerful Student Council (which, ya know, actually does something important), while Tamaki is in charge of the Host Club, which is probably the most useless thing second most useless thing ever.
 * The Host Club has 7 boys, 1 girl (not including the manager), while the Student Council has 3 girls, 1 boy. And Rivalz.
 * Tamaki is a loser who tries to look cool, while Lelouch has an aura of coolness around him.
 * Tamaki thinks small, caring about himself more than anything. Lelouch thinks big, like.

So in conclusion, if Lelouch and Tamaki went into the same room, the universe would explode. Unless Milly and the others were there with Lelouch, whereupon it would evolve into a full-scale war that would consume at least a story arc before collapsing under it's own weight. Hell, let's throw Haruhi Suzumya, and a couple time lords in there, too.


 * I hate to disagree on WMG but I think most Ouran fans would agree Tamaki's not a loser, and selfish? He's constantly trying to get the Host Club to help other characters, including the Newspaper Club who was out to ruin his name. I mean, have you even seen or read the series? I'd argue that Lelouch is far more selfish because his reasons for his plan are all because of his sister's wish. That's selfless on a small scale, but considering  I think that's more selfish.

The Hitachiins are alternate universe Weasley Twins.
They're red-haired trouble-making twins who enjoy fucking with everyone.
 * Does that mean one of them's going to die in an explosion?
 * This is actually more or less confirmed by Word of God.

The whole of Ouran High School is real, these are just their memoires as written by Renge

 * Renge, at one point is said to have created a hugely popular doujinshi about the hosts. So that is what we are reading/watching, while the real person on who Renge is based, is now richer then the other kids from it. It would explain the over the top fighting, she wanted to make the real life happenings more interesting for readers.

== There is an canonical alternate meta-universe to the main anime series where each character is the main character, instead of supporting cast (homosexual or otherwise). == The alternate-universe series include:
 * A French-Japanese boy gathering a surrogate family while planning to escape the controlling clutches of his grandmother and find his long-lost mother.
 * A young man whose forbidden love for his brother is seen as a joke, and his struggles to reconcile their drifting apart as the brother falls in love and the main character must learn to deal with the jealousy and allow his loved one(s) to be happy.
 * A young man whose comical twin brother helps him win the heart of the girl before the Rich Idiot With No Day Job can, but only after learning to open his scarred heart.
 * A man who struggles to cope with a world that sees him as a monster, a man, and a child, and wants to overcome the outdated traditions and boundaries of his family.
 * Mori the Combat Butler.
 * An Oblivious to Love lower-class girl who seeks to repay an accidental debt, and gets into all sorts of wacky and romantic events when the only way to repay the debt is to pass as the male member of a high school mock-Host Club.

These all, of course, contrast the actual story (the one that focuses on an Asexual Inadequate Inheritor and "Well Done, Son" Guy realizing with the help of his elder sister that he must surpass his father rather than merely gain approval, and in a major subplot with his Ambiguously Gay Vitriolic Best Bud learn to love instead of only using people for political or financial gain).

Kyouya is actually in love with Haruhi.
In chapter 64, when Haruhi is kidnapped, Kyouya says, "I also never thought of getting involved with Haruhi. I thought that chasing her would've been dangerous." So... he didn't pursue her because he thought his position made it dangerous for her?
 * This is only in the scanlation. The official translation reads a bit differently: "Although I'd planned for the eventuality of Haruhi being targeted for associating with us, it's apparent my preparations weren't adequate. It was an oversight on all our parts".

Furthermore, in the last chapter, after Hani asks him if he was in love with her, the end of his reply is  Hiding his feelings so the two can be happy together? Oh, Kyouya.

Honey and/or Mori is omniscient
Right after the eye-catch in episode 10, the two of them (in somewhat trance-like voices) what happened leading up to that moment from off-screen, when they hadn't witnessed the events in the first place.

There are numerous other moments where one or both of them seem to (quite accurately) understand everything that's going on much better than any of the other characters, whether in-verse (discussing everyone else's feelings while up in a tree during a game of kick the can), or slightly breaking the fourth wall (when Honey seems perfectly fine talking about ).

Honey, Mori, and possibly Kyouya are Saiyans
Honey is extremely strong for someone his size. It's not because he's a trained martial artist. He's a saiyan. Notice how he eats so much cake? Think of how much Goku eats. It's regular for a saiyan. Mori is a saiyan as well. We just don't see him eat on camera. Kyouya, however is dificult. He doesn't use his strength often. He DOES however use it in the last episode of the anime. He puts a dent in the hood of the limo. But he only uses a bit of his strength. He actualy hits it with all of the force you would use to slam down a pencil. Therefore, three of the hosts are saiyans.
 * Tamaki is also a Saiyan. He went Super Saiyan in the second Kasanoda episode.

Kyouya is Light
Well, there are already two different theories that either his notebook or clipboard is a Death Note.
 * Alternately, he's Mikami and Tamaki is Light.

The Suoh family is related to the Takamachi family
In fact, both are descendants of the Fuwa samurai clan. That's why both Tamaki and Nanoha have access to the fabled Starlight attacks (Starlight Kick and Starlight Breaker, respectively)--it's an ancient technique that has been passed down in their families for generations!

Haruhi is genderfluid/genderqueer.

 * Hardly a Wild Mass Guess, or even a guess at all. She says she doesn't put much stock in gender, in a way that makes it seem like she doesn't bother to identify as anything, since it's not really important. E.G., "genderfluid".

Tamaki is related to Kei Agemaki
They're both clearly intended to be the cutout prince character of every shoujo series (Which, if the way Tamaki's dad acted near the finale is any indication, runs in the family), but they're also these huge dorks who rather quickly develop a crush on the main girl who's shown as more competent at them (Zakuro at fighting Youkai, Haruhi at... being an Only Sane Man among a bunch of wierdos.) and... well, they look similar. Plus OYZ takes place in the Meiji Era and Ouran takes place in the present. Considering Tamaki's half Japanese, theoretically if Kei and Zakuro's kids intermarried with enough humans for the Youkai-ness to wear off over the generations, this could work. (Or, hell, maybe Tamaki has Youkai powers and just doesn't know it yet.)

Haruhi is related to Hideyoshi
Not only do they look simalar, they have the same attitude about things. Plus, Hideyoshi is a boy constantly mistaken for a girl despite his protests, who might actually be Prettier than his sister. Haruhi is a girl who is assumed to be male by most of the school. Basically, we have a trap and a reverse-trap who look identical. They are probably family. Maybe cousins.

Kyouya and Hiruma are long-lost brothers
Both are calculating, athletic, tacticians who have notebooks of disaster.

Kyouya does consider himself and Tamaki to be Platonic Life Partners.
...But he considers himself to be the fiscally responsible, emotionally stable father and Tamaki to be the emotionally wild heiress mother who provides direct care for the children. If only Tamaki referred to himself as the mommy and Kyouya as the daddy, Kyouya would gladly endorse it.

Ouran takes place in the world of Toy Story
And that's why Usa-chan blushes, and Yasuchika saw it move on it's own.

Kyouya really was trying to rape Haruhi in episode 8
Then he wasn't trying hard...

The reason why Ayanokojini, Tamaki's customer in episode 1, is so nasty is because she has been abused, neglected, and / or bullied
When Tamaki takes an interest in Haruhi, it's quite obvious she is very, very, VERY, jealous. Perhaps she is a Broken Bird whose relationship with Tamaki is the closest she has ever gotten to truly loving someone...

Honey is the most well endowed of the group
And Tamaki is the least