Johnny Depp mooned a teacher while in high school.

Johnny’s account as he remembers the incident:

"There was this vicious woman, a teacher. If you weren't in her little hand-picked clique, you were ridiculed and picked on. She was brutal and unjust. One day she told me to do something...her tone was nasty. She got very loud in my face in front of the rest of the class and tried to embarrass me. I saw what she was doing, that she was trying to ridicule me. I turned around and walked away. As I did, I dropped my drawers and mooned her.”

As a result, Depp was brought before the dean of discipline, who suspended the future actor from school for two weeks!
(source)