Put googly eyes on all of their belongings. This is a simple but effective prank that's sure to get a chuckle. Just grab a pack of googly eyes and start sticking them on everything you can find, from their toothbrush to their computer monitor.
Change all of their alarm clock times. This is a great prank to play on someone who's always running late. Just sneak into their room and change the time on their alarm clock so that it's an hour earlier than it should be. They'll be in for a rude awakening when they wake up!
Hide all of their keys. This is a classic prank that's sure to cause some frustration. Just grab their keys and hide them somewhere they won't be able to find them easily. They'll have to search the whole house before they can leave!
Put a whoopee cushion on their chair. This is a timeless prank that's always good for a laugh. Just place a whoopee cushion on their chair and wait for them to sit down. They'll be in for a surprise when they hear the loud fart noise!