Me and my cousins shook up my uncle's beer after he came from the bar and we put it back in the fridge. He was very drunk and he asked us for another beer and we gave it to him it squirted all in his face it was so funny. And he chased us all around the house mad as ever lol.
Senior prank I read about, didn't do this one myself... These seniors set up a system of pipes in the school library, then filled it with paint, then pressurized it. After all was done, they left behind an instruction manual on how to take it down. The janitor did not believe the note one bit, and then the library was covered in paint =)