What you need:
-Faucet that is both used by the public, and has a hose attachment.
-Clear tape or rubber band.
Clear tape is far more effective, because you can barely see it, but it may leave a residue on the handle.
PS. I just read that it has to be new and creative, so i guess I should have read the rules three times before making this.
Step 1: Wrap the Rubberband
For those of you using tape, just hold down the button and tightly wrap the tape around the handle. make sure it sticks.
Step 2: Aim and Set
For an extra shock, run the cold water for a few seconds, and then shut it off. This way, even if they turn on warm water, they will still get a chilled blast, depending on how long after you set it they get blasted.
Remember to prank safely and have a happy April Fools Day!