At the play November with Nathan Lane, I followed my normal habit of switching to an orchestra seat at intermission from my TDF mezz seat. Sat down next to an older white-haired man, tried to chat him up a bit--also as per my usual--and he wasn't very friendly at all. As I was leaving, someone else pointed out to me that I'd been sitting next to Phil Donahue and Marlo Thomas; too funny, didn't even recognize him and he probably thought I was bothering him because he was a celebrity. Did then chat up Marlo in the aisle about the play, just for fun...until Joe Mantello walked up and comandeered her.
Come to think of it, I also met Oprah back in the early 80s when we were both journalists in Baltimore and she blew me off, too! Maybe I have bad luck with daytime talk show hosts

Have gotten a smile and hello from Gloria Steinem and John Malkovich when each of them was sitting near me on different occasions.
But the most exciting had to be sitting a couple of seats away from Liam Neeson while watching Alan Bates and Frank Langella in Fortune's Fool...we were all in the second or third row and to be so close to all those amazing actors kind of blew me away!