Carefully open a small bag of chips by pulling apart the top, then remove the wafers. Replace them with some other type of chip, or fake cardboard "chips." Then glue the top back and offer them to your victim.
Place a "For Sale" a notice on your victim's car. Quote a very low cost, yet a realistic realistic one and don't forget to mention victim's phone number.
Take a slice of cream cheese or jelly and carefully insert it into the deodorant container after scooping about an inch of deodorant from the top of the victim's stick deodorant. Sculpt cheese or jelly well so that it looks like a deodorant. Put the top back on and wait for the fun!
Stuff victim's shoes with some cotton, when the person will try wearing it they will feel that either their feet have swollen or the shoe has shrank.
Block the signal on the TV remote with a tiny piece of black paper, or use a small piece of black electrical tape.
Prepare a special sandwich for the victim. But don't remove the wrapper from the slice of cheese. When they bite down the victim'll get a chewy surprise.
If you're a woman and have a boyfriend , this prank is for you! Put a pair of female panties & put them in your significant other's vehicle. During a drive, locate the underwear and create scene! After he gets upset, tell him 'April Fools!'
Find a small picture of a a funny creature (monkey, donkey, baboon, etc) and use a glue stick to place it over the photo on victim's driver's license. Then send him out for beer, or have some better excuse to send them somewhere where they need to show their ID.
Put a small amount of paint or ink on your finger. Go up to your victim and pretend to notice a "mark" on the victim's face. Tell the victim that you'll rub it off. Instead, actually place a mark ON their face. Act like you got the mark off and walk away.
Record the morning news telecast of the rainy day when schools were closed due to heavy downpour/snow. Then play it back on April 1st in the morning while the kids are getting ready for school.
Swap the phones of the victims who own similar makes and models but keep them in different color cases, giving each person back the correct case, but the wrong phone!
Try covering the urinal with a good quality cling film, tie it tightly so that its not visible at at a glance then wait to see who gets splashed first.