In the movie "its a wonderful life" the cop and policeman were named Bert and Ernie- which Jim Henson later used for the muppets.

My favorite line in "Guess who's coming to dinner" is when Sidney Potier says "My wife hopes our baby will grow up to be president, but I would settle for Secretary of State" Quite a prediction

Also, in Blazing Saddles, in the bar screen they talk about the Anthrax scare. (for cattle)