Not exactly Zelig (or Forrest Gump!) here, but I’ve had my share. Like @Brian1946, I’ve had “a few brushes with fame,” although probably none of them I would call “great”.
As a child, I grew up in an artistic family. At gatherings and parties, I met people such as Carl Anderson, Ross Bellah, and others in the arts and film community in Los Angeles.
When I was in high school, I worked on the campaign of a woman who was the mother of a classmate. While doing canvassing, I was paired with another woman. As we were going door-to-door, we did our little speeches promoting the candidate. After leaving one particular house, where we spoke to an older man, she turned to me on the walkway and said, “You know who that was? Karl Shapiro.”
In college, I worked for a day as an extra on a straight-to-video movie that starred Brian Austin Green.
Again, like @Brian1946, living in Los Angeles means if you’re not being a hermit, it’s kind of hard not to pass by a celebrity; I won’t post all that I’ve seen (charity events, book signings, etc. are more run-of-the-mill things where celebrities are advertised as being present, and seeing one is expected); just a couple of the more interesting ones.
A few years ago, I was at the library, and went to look up a book in the catalog on the computer. While waiting for the results, I glanced casually to my right, and saw Danny De Vito using the catalog as well.
I marched in the anti-war protest in Hollywood in 2003, just prior to the start of the war in Iraq. To my right was Tyne Daly, and just behind us was James Cromwell.
My latest was about a month or so ago. I went to the art museum to see a new exhibit, and as I walked up the front entrance, I turned around to see if my companion was right behind me, and I looked straight into the (very!) blue eyes of Owen Wilson. This was just after I’d seen “Midnight in Paris”, so it was slightly, vaguely, remotely serendipitous, I suppose.
Right now I’m friends with a writer who I predict is going to be very well known, more so than she is now, someday. :-)