Bell, Book, and Candle: Jimmy Stewart to ex-girlfriend talking about Kim Novak [a witch]: "No, you don't understand, she's a witch." [Her reply], "Oh Shep, you just never learned how to spell."
Steel Magnolias: Olympia Dukakis: "If you can't say anything nice about someone, come sit by me." Shirley Maclaine to Darryl Hannah's remark that things just couldn't get worse: "Of course they can."
Blazing Saddles: Madeline Kahn to Cleavon Little: "Tell me, is it twue that men of your persuasion are ... uh ... gifted? [pants unzip] Oh, it's twue, it's twue."
Midnight in the Garden of Good and Evil: The Lady Chablis being rolled into ER on a gurney: "Oh, Oh, either it's my appendix or my water broke."
History of the World, Part I: Moses coming down from the mountain with three tablets: "I have fifteen [one tablet falls and shatters] ten, ten commandments."