thanks for the tips! I think it will really help this weekend, I especially like the "It has to look really really cool" tip. I really think that having really fancy looking demo is key to getting people excited about your product, even though that's not how it will be when you finally launch.
Question to those who have interviewed for YC before: Is it structured so that we can present from beginning to end, or should we expect to be fired with questions and possibly get a little sidetracked before finishing?