A teacher in Vacaville, California was a victim of the "stapler in the Jell-O" prank. He figured out that it was the janitor, but thought it would be funnier to blame one of the kids. So he set up a videorecorder before class and pinned it on a student . . . and even made the kid remove the stapler from the Jell-O.
Here's the scenein "The Office" where Dwight finds his stapler in Jell-O.