Well I've *seen* lots of them, at lectures, live shows, concerts...I used to live in Hollywood so there were a fair few floating around there making appearances.
Bill Cosby was the speaker at my university graduation, and I met Ray Bradbury and Doug Adams at my university bookstore (Bradbury ruled and Adams was kind of a jerk). I got to hang out with Glenn Shadix once (I run the big cartoon Beetlejuice website and my friend Shaun ran the movie one as well as Glenn's site, and I hung out with Shaun and Glenn at Universal Studios one day). He was really nice. And cute.
And of course I've met folks who work on Foster's, but y'all know that. There's probably more, I don't mean to leave anyone out, but I'm kinda wiped out right now.