Annoyed by their anatomy professor's telling of off-color stories during class, a group of co-eds agreed that, as soon as started to tell the next one, they would rise and leave the room together in protest. The professor got wind of their scheme and started his lecture with: "They say there's a terrible shortage of prostitutes in France."
The girls glanced at one another, stood, and headed for the exits.
"Sit down, ladies," said the professor with a big grin.
"The next plane doesn't leave for hours!"