First, we did the usual, suran wrapping the toilets. We also occasionally dropped a pair of granny-style underwear in the hallway... to cause a scene.
Next, we filled all of our lockers with alarm clocks and they all went off at the same time.
We also had a group of the graduating boys, wearing ski masks, capes, and speedos, ride bikes through school, screaming "we are the seniors, and we are the best"
The best of all was when the seniors had a tale-gate party in the parking lot before school. They slep there for 3 days. While they were there they put a dead deer, that was dressed in clothes, in a lawn chair on the school's track. They also put signs around town (by the burger place, our football stadium, our schools main entrance, the bowling alley) that said "SENIORS ROCK".