When asked to describe myself, I usually fall back on saying "I'm a total geek." Nerd/geek/dork - I'll answer to any of those; I've long since decided to embrace it.
True to form, i'm into all of the stereotypical geeky stuff: computers (programming, playing games, endlessly swapping out parts), reading (though my attention span for Serious Books is not what it once was - I blame the Internet), and Dungeons & Dragons (ask me about my username!).
Beyond that, I like deep conversations about things that are interesting (which is pretty much all the things). I like learning about stuff I don't know anything about, and exploring new places I've never been, especially if I have a partner or a guide.
In terms of politics and philosophy: I'm a skeptical agnostic secular humanist militant feminist egalitarian progressive liberal utilitarian libertarian. I see no contradiction there, but if there is any, well, I think my buddies Whitman and Emerson have got my back.
 It's tempting to try singing that to the tune of "I am the very model of a modern major general", but it doesn't quite work, alas.
 I'm not actually friends with any 19th century poets, but I think they'd totally be cool with me name dropping them to impress chicks on the internet.
I'm an introvert. That's not to say I'm a shut-in! I like people and going out and doing things with them, but I do prefer small groups to huge crowds, and I need a fair amount of alone time to recharge too.
My sense of humor is about 60% fluffy goofball absurdity, 35% cynical sarcasm, and 5% totally twisted.