Grades 7-9 the hell raising years of Jr High,
I would spend all of my Social Studies class doing anything but schooling. Throwing textbooks into the courtyard in the middle and spending the next 20 minutes meandering the halls to retrieve them. In this same class I'm pretty sure I spent 2 full classes taping a piece of presentation paper over a vent that was blowing cold air.
Friend blowing a hole through the arts room window with a home made pipebomb and proceeding to need to run to the closest alley.
The popular Snowball at vehicle exercise resulting in a much slower adult getting out of said vehicle and chasing us, as well as rocks at seagulls.
And my favorite would be when I discovered that bobby pins plus electrical outlets equal "sweet balls of spark everywhere" usually I would do it in empty hallways, until my final episode outside of Miss Lim's math room during class change, of course the packed hallway went crazy which proceeded to Miss Lim running out and asking who did it. Could of just said nothing and no one would of been in trouble, but nope got the one kid who yelled my name and pointed to me, End Result was a trip to the office and having to write a report on voltage.
Good times....