1) Take him to lunch, when he's not looking, suck ketchup into his straw and place it back into his drink.
2) take a rubberband and wrap it around the sink sprayer nossle so it's button is engaged. When he turns on the sink water it will give him a shirt full of cold spray. (make sure sprayer is pointing forward)
3) When he's in the shower, fill a large glass of ice cold water and then ... sneak in and throw it over the shower curtain. (do NOT do this if he has heart problems!)
