1. Tell your friends you got a bad tattoo on your butt, and you're too embarrassed to show them. You'll really have to sell it and use your acting skills. Then on April 1st, tell them you're finally ready to show it off . . . and moon them all at once
2. Buy some Rain-X . . . the stuff you put on your windshield. And use it to write creepy phrases on someone's bathroom mirror. So when they shower, that part of the mirror won't fog up, and they'll think their house is haunted for a month.
3. Go to Goodwill and buy a bunch of cheap Hummel figurines. Then pick a friend or relative, and start leaving them in random places around their house. The more figurines, the better. Then on April 1st, reveal it's a prank.
4. The penny prank. This one's similar, and easier to do if you live with the person. Start by leaving one penny a day on the floor somewhere in your home, so they'll find it. Then around week three, start leaving them in weird places pennies shouldn't be, like the shower. The key is to always deny you're doing it, and keep a straight face.
5. Bring a big bottle of communal hand lotion to work, and tell people it's for everyone to use. A few of them will probably love you for it and think you're great. Then let them get in the habit of using it for a month . . . and on April 1st, fill it with lube.