Put a latex glove or water balloon with a small puncture on the side facing you on the sink faucet. When someone goes to turn it on it'll spray on them. We do this all the time at my work.
Lift the toilet seats and stretch cling wrap across ... Next deny all knowledge of the act
when I was 16 I painted the toilet seat with nutella, plus some brown fingerprints on the walls. My dad was in shock for a few minutes
Is there any Jewish neighbour hoods near you? Run through there with some money on a string