Simple, set-up in seconds, and will more than likely ruin someone's morning... I think that is the textbook definition of a April Fool's Day Prank... This was a classic prank around my house growing up, not just on April Fools Day, but the closer we got to the day of pranks, the more it happened.
Here's what happens: Someone decides to make coffee in the morning. They get the pot ready, turn on the water and BOOM!!! They get drenched! You've rigged the kitchen sink to default to the sprayer the second the water is turned on... It. Is. Priceless. Trust me, nobody EVER checks out the sprayer before turning the water on.
WHAT YOU'LL NEED:
-- Kitchen sink with sprayer
-- Rubber band, hair tie, or even plain old string... (I prefer rubber bands)
-- Running water
THAT'S IT! EASY!
STEP 1. Wrap rubber band around the trigger of the sprayer
STEP 2. Wait for a victim. When your wife, brother, sister, or friend go to turn the water on, the will instead get soaked by the sprayer!
STEP 3. Deny involvement with the prank or claim your victory and run for your life. Either should keep you out of immediate danger.
That is all there is to this great classic prank. It really does stand the test of time. I'll be doing this until I'm an old geezer, or until someone murders me for getting them all wet right before work... either way, I laugh every time.