One I thought would be great was a few years ago when I first moved to LA I wrote up a fake eviction letter and slid it under the door for my gf at the time to read. It said she was being kicked out because she was not providing enough anal sex
However... she got home WAY early than I expected and I wasnt there to see the joke. come home to find her on the steps crying on the phone with her mom saying we got evicted from our apartment. In short, that joke did not go well.
One that did was when I was in college, a friend and I tied all the doors together on the girls side of the hall in the dorm, so about 20 doors. Pulled the lights out of the ceiling and covered the floor in shaving cream and pulled the fire alarm.
No one ever knew it was us, but was sure funny to hear about how they had to call public safety to come and cut the ropes the doors were tied with and girls falling because of the wet floor