There was an old professor who started every class with a vulgar
joke. After one particularly nasty example, the women in the class
decided to walk out the next time he started. The professor got
wind of this plot, so the next morning he walked in and said:
"Good morning, class. Did you hear the one about the shortage of
whores in India?" With that, all the women stood up and headed
for the door. "Wait, ladies," cried the professor. "The boat
doesn't leave until tomorrow!"