From 7am to 8:30pm, I was on the set for the film DOUBT, as background talent for a church scene with Phillip Seymour Hoffman and about 500 extras. It was a bit crowded!
While it was a very long day, it was rewarding in that I had a chance to see Phillip Seymour Hoffman and Meryl Streep (only briefly though, in her case) in action.
I thought Mr. Hoffman was pleasant, professional and funny. When he wasn't delivering sermon as sermon (as Father Flynn) he cracked a few jokes. As I said, I only saw Ms. Streep briefly, but of course, all eyes were on her when she was there.
The crew on the film overall was very warm and professional, as was director John Patrick Shanley.
Overall, I wouldn't say I had fun, but it was an experience. I don't think I need to do it again though. Doing background is nice a few times, but after a while, you start to feel like a piece of furniture.