Oops. I probably should have done this a while back, but I never logged on to the root level of the "Off-Topic Forum" to see this sticky.
Anyway, I'm Damian Chadwick -- I've been taking classes at the UCB since last February. I took level one after making a blood oath with a friend of mine to sign up together. Friend backed out, and I dragged my sweaty, nervous self alone to Jackie Clarke's class and went through with it. To be honest, I really didn't know quite what I was getting into at the beginning. I'd only seen like one show at the UCB and was very unsure how improvisation worked.
If improv had turned out to be some series of gags or tricks I'd probably have gotten sick of it pretty quickly. But of course it really isn't, and I was quite taken with how it had evolved into this amazing flow of ideas on stage. When I try to explain it to friends, I tell them that a good improv scene should unfold like any social interaction. When you're on a bad date, or having a dull, awkward conversation at a party or something, you're constantly "in your head" thinking of the next thing to say. When a conversation is going well and you're grooving with a friend or someone you like, it all just unfolds. You're joking and laughing and saying witty things without trying. Improv, I tell them, is exactly like that.