In the movie 300, Leonidas asks the oracle for permission to release the Spartan army from the holiday games to do battle with the Persian army.

When he pays his tribute and lays out his plan, the creepy old guys go to consult the oracle, a young girl in a very sheer slip.

They pose the question and she starts to dance. The beginning of the dance has her the slip tied on her right shoulder with left breast uncovered. Then in the middle of the dance, the slip is tied on the left shoulder, covering both breasts. Then a cut to them watching, and when it goes back to her, same as the beginning, slip on the right shoulder, left breast uncovered. Toward the end of the dance, the slip's on the right shoulder, everything covered. Hey, it's a slip-up with a slip!