1) I was in preschool, and one day during naptime I decided I didn't want to sleep. No one ever actually napped during those anyway, and they were all attempting to socialize or put blocks together and make pretty colors and whatnot. So, I was bored and pulled down my pants and mooned the whole class. I don't even know why.
2) I was in 2nd grade, and it was around Halloween. The teacher just left the room and then jumped back in, wearing a scary-ass mask. While most of the normal kids screamed and had a good laugh, I pissed myself.