Adorkable/Real Life

Jeffrey Combs. Has anyone ever seen an interview of his? Yeah. Totally adorkable.
David Tennant. His foreword to the Doctor Who Specials boxset is heart-meltingly sweet.
Jayma Mays often looks like she's trying to stifle a laugh for fear of snorting.
Leonardo DiCaprio. His real-life persona. He watches Barney, goes on Youtube and searches for obscure stuff like; 'frogs mating', makes slapstick jokes on the set, is a comic book and baseball card geek, watches 90's anime...

Claire Danes: When I first met Leo I was quite shy and nervous but he was very easy to get along with, [...] In fact I found him quite geeky...but an entertaining geek (laughs)

The Glee Project candidate, Cameron, who embraces his dorkiness. Not surprisingly, he was a fan favorite before the show premired.
Mark Hamill, as shown in his episode of The Muppet Show. The Muppets shoot down every one of his "entertaining" suggestions, leaving him to sneak on stage to gargle Gershwin with an argyle gargoyle.
Koshi Inaba of B'z. Smart, shy, sensitive, nice guy, love dogs, a big bookworm even after becoming famous. In fact, his dorkiness is one of reason he is so popular. That, and being very HOT.
Dustin Hoffman, especially when he hit the big time with The Graduate.
Michael Jackson. Being a Large Ham Keet in some company but soft-spoken and kind in other company were a few of his most endearing traits. Fans (and anyone else whose bothered to look) have had access to some of his more private moments caught on tape for years, providing a much more vivid and honest display of the type of man he was. From dancing to R. Kelly's "Ignition" to being picked on during his simulated normal person's Publix visit, it's difficult to not find the guy charming and likeable.
Rachel Maddow is charming, adorkable, unabashedly liberal, a fantastic bartender, exceedingly well-educated and -read (a Rhodes Scholar and a Ph.D in public policy) and will quietly rip your guts out if you lie to her in an interview.
Jon Stewart combines biting snark with endearing awkwardness. Fellow Comedy Central fake news pundit Stephen Colbert has his moments too.
Ironically, Jensen Ackles. While the character he plays in Supernatural is basically the epitome of cool, Jensen himself is very shy and looks like a deer caught in the headlights when he gives an interview.
Brett Domino and his other band members run on this, which is a factor in making them so entertaining.
Ladies and gentlemen, I give you Sir Paul McCartney. Making mashed potatoes.
Cristina Valenzuela, in addition to many characters she voices.
Believe it or not, the seemingly cold and aloof Russian figure skater Evgeni Plushenko is this. Just watch his expression after he fell on his jump.
John Oliver, one of the many talents first featured on The Daily Show. As a bonus, his british accent is to die for.
Michael Cera. There's a reason he always plays socially awkward sweet guys.
Hayden Christensen, despite being best-known for playing a semi-jerkass who turns evil, is actually quite humble and sweet in real life... as evidenced by his behind-the-scenes footage. He shows elements of being a Promoted Fanboy, too.
Madeline Zima. Watch any interview with her, she's like a hot chick version of the vulture from Looney Tunes.
Britney Spears, was always a dork, but now she's really letting it all out.
Alexis Bledel seems endearingly awkward during live interviews.
Scout Taylor Compton. Kind of hard not to be with that nose.
Jesse Eisenberg. Not only is he ridiculously awkward (and adorable simultaneously, which already qualifies him for this trope), his hobbies include taking old maps and drawing the new countries where they belong in Sharpie. He also reads, doesn't watch television, and produces hilarious lies in the middle of interviews. And he fosters cats. Basically, he's awesome, as well as being practically the definition of this trope.
Steven Spielberg in his youth.
Jennifer Lawrence, as demonstrated in this interview with David Letterman to promote The Hunger Games.
Benedict Cumberbatch. Yes, really.
Also Martin Freeman, "the man who is made of kittens".
Masi Oka is just plain made of adorkable. There's a reason Hiro and Max are so nerdy (Masi even once admitted that Hiro's personality is basically his own with an extra dose of happy naivete).
TV Choirmaster Gareth Malone. Just look at him!
Archibald Wavell, British General and reclusive poet.