The one that my class did (I won't say if I was personally involved or not) that were not previously mentioned involved the massacre of several animals such as squirrells and birds. They were then placed in a very large glass "jar", which was filled with water, capped, and placed in the sun for two weeks. Then the jar was broken on the floor in a busy area of the school not long before people changed classes. The stench from it was something I've never smelt in my life. The kid who broke it was seen by the band teacher and she looked him up in the yearbook and narced. He came very close to not graduating and had to pay for new shoes for the janitor that cleaned the mess up.
One that a few classes ahead of me did was they stole a massive amount of Crisco baking oil from a local supermarket and they spread it all over the hallways. Nine students were either expelled or had severe suspensions, and each had to pay several thousand dollars for the gym floor that was ruined by the oil tracking into there. A teacher broke her arm and several people were injured. However, I still chuckle when I think about that and it goes down as the best senior prank I have ever heard of.
