Jumping past the usual "I'm not great at summarizing myself" etc (which is true), I'm a geek who's usually an introvert, but trying to be an extrovert.
I have sarcastic sense of humor, a knowledge of obscure (but interesting) trivia, and an amazing ability to have extended conversations on topics I know very little about (I ask a lot of questions).
I also like incredibly garish shirts. The brighter (or "more hideous", as one of my friends puts it), the better.
I'm willing to try just about anything at least once (except bungee jumping -- If I'm jumping from a high place toward a low one, I'd damn well better have a parachute strapped to me).
I use parentheses a lot (like this, if you haven't already noticed). Probably more than any sane person should.
Oh, and I have a TERRIBLE sense of direction. While the fact that most streets in MA either lack street signs (or change names a dozen times in a mile) really doesn't help, I still suck at finding my way around this damn state. Google Maps is a godsend.