1. This one's for diabolical parents: When the kids are sound asleep, switch them to each other's beds. Just make sure you're there to see their reactions when they wake up!
2. Change your victim's cell phone settings from English to another language.
3. Replace the cream filling of Oreos with toothpaste, then invite your target for a snack.
4. Add a few drops of food coloring to the bottom of a cereal bowl. When your target pours in milk, he'll get a colorful surprise.
5. Sprinkle grape Kool-Aid mix inside the showerhead to turn the water—and your victim's skin—purple.
6. Place mini marshmallows on top of the ceiling fan's blades, then ask someone to turn it on.
7. Fill soap dispensers around the house with pancake syrup.
8. Spread a layer of cream cheese over your target's deodorant.
9. Switch your friend's cell phone background image to a photo of cracked glass.
10. Fill an empty mayonnaise jar (with the label still on) with vanilla yogurt while no one's looking. Then, when the family is in the room, grab the jar from the refrigerator and dig in to the "mayo."
11. On Facebook, change your birthday to April 1. When the well wishes start rolling in, switch your status to "April Fools!"
12. Take a screenshot of your coworker's computer desktop, and set it as the background. Hide all of the desktop icons and watch as she struggles with the "frozen" screen.
13. Post a sign on the office copy machine that says, "This copier is now voice-activated."
More stupid humor...
I poured their cereal with milk the night before and put a spoon in it, then popped it in the freezer overnight. Took it out the next morning and they couldn't get their spoons out. Very funny. Also, one year I replaced the raspberry jelly in their doughnuts with ketchup. That didn't go over as well!