Alexis is a really funny guy. This took me back to Reddit's Startup School talk last year at Stanford. Alexis and Steve did a slideshow presentation, and it was hilarious.
I was sitting in the back row last year and I watched him prepare the presentation during the afternoon. I didn't know what he looked like at the time but seeing him work the alien on his laptop was a dead giveaway. And yes, I did talk to him and asked about his YC experience. It certainly made the idea of doing startups more real to me. (Sigh... working at a job-job these days, but still dreaming.)
For those of you who are going this year - remember to talk to other people; meeting other like-minded hackers is part of the Startup School experience.