I never played pranks in high school, but helped with a few in college. My boyfriend (now husband) had a dorky but basically nice freshman roommate. Mike and I, lordly in our upper-class might, wasted no opportunity to torment the poor boy.
Pat had a characteristic habit of walking into the dorm room, yanking open his closet door, and staring into his closet before finally hanging up his coat or backpack. These were large closets for a dorm; you could actually walk into them (when empty). So, one day we removed all the screws holding the doorknob in place, then removed the pins from the hinges.
He walked in, yanked on the doorknob... and it came off in his hand. He stood there, staring stupidly at the knob, as the entire closet door came off its hinges and fell on him.
We're lucky we didn't kill the poor boy. And he still came to our wedding!