On the morning of April Fool's Day, go on Facebook and change your birthday to April 1st. Wait for all your friends to wish you a Happy Birthday, then laugh hysterically!
Buy a can of fake snow. Early on April Fool's Day, sneak outside and spray the fake snow around the edges of your victim's bedroom window. Put some more on the ground wherever it will be visible from inside. Now wake up your victim and tell them it snowed during the night! This prank works best on a child or on the very gullible! Note: if you don't have fake snow, you can try tricking them with some mashed potato flakes.
Print out this word search puzzle and give it to your victim. It looks like a normal word search puzzle, but none of the words listed at the bottom of the page are actually in the puzzle. So your victim will search and search endlessly, until they pull their hair out in frustration. Wait until just the right moment to point out that the words "APRIL" and "FOOLS" are in the puzzle!