In the scene at the comedy club in Lubbock Texas, when the old woman, Peaches Davis (II) throws the beer bottle (a rubber prop) at Richard Dreyfuss, on the 1st take the bottle struck Dreyfuss squarely in the crotch! The entire cast and crew, including Dreyfuss, was laughing so hard it was several minutes before shooting could resume.
The "for Paul Mazursky" dedication was for a friend of writer / director, Greg Pritikin. The two of them used to eat breakfast at the farmer's market in Hollywood with a group of old comics, and Pritikin says the stories these guys told inspired this movie. The end of the credits list some of the comics that were there.
In this film, Chevy Chase plays a character named Al. Thirty-plus years prior, Chevy Chase lipsynced in the popular music video to Paul Simon's song, Paul Simon: You Can Call Me Al (1986).
Three Degrees of Bill Murray: Richard Dreyfuss starred in, along with Murray, in What About Bob. Bill Murray took Chevy Chase's spot on Saturday Night Live. Both also starred in Caddyshack. Andie Macdowell played the love interest of Murray's character in Groundhog Day.