Well, I live in Los Angeles, so star sightings just aren't quite as big of a deal.
Let's see... I've seen a lot of celebs, but almost always, I don't recognize them, or don't know until someone points them out to me. As far as I can remember:
-Queen Latifah was my next-door neighbor for a while - she autographed my copy of the Chicago soundtrack.
- I've been at school with Corbin Bleu (he was in Catch that Kid and Galaxy Quest) and Alex Linz (he was Max Keeble, and in a lot of other stuff), and I still see them occasionally
-I went to theater camp with the Olsen twins' younger sister, and I saw them at the performance
-I met Alex Trebek when I was on Jeopardy
-I met Big Bird (XD) and a lot of other people from Sesame Street when I was way younger and on one of the videos. I got a feather, heh
-I once saw Winona Ryder shopping
-I interviewed the author Orson Scott Card (over e-mail though)
-Dunno if this is too political, but without any espousal of beliefs whatsoever I've met Bill Clinton, John Kerry, and a ton of other political figures. And I have autographs!
I know there are quite a few of my mom's friends work in TV, but I forget their names, and I don't really know how famous they are anyhow. And...uh, once at a writing club, I met a two of the actors/actresses from one pretty popular TV show... but I forget what it was. Plus, I get to go to premieres on occasion from this movie club, so sometimes I'll see the actors/filmmakers but generally it's not close-up although once or twice I got to say, like, "Hi."
And this is all with me not being really into the entertainment biz.