I know someone who thought it would be a good idea to drop a pane of glass down an elevator shaft in the gap between the elevator car and the floor.
To finish the story, when they replaced the cables, a wooden cable spool was left behind.
Some other people decided it would be a good idea to take the spool up on a hill and watch it roll to the bottom.
It hit the campus cop car on the way down. Good thing it wasn’t a real cop.