My father used to do Transportation on films shot in Chicago, and so he got to know quite a few movie stars. Became very friendly with a few of them (Joe Pesci, Daniel Stern, Kelly McGillis, David Duchovny). Of those folks, Dan Stern was the only one that I've met, personally. Seems like a really nice guy.
Other than that, Dave Draimain (Disturbed) is a guy that I wouldn't really say that I KNOW, but he grew up and is really close with a friend of mine. We've hung out a couple of times and, from what I can remember, he's also a really nice guy. Haven't seen him since before his band made it big, though.