neatly wrap a toilet bowl in that stuff, then when a friend goes to take a pee or crap he will splatter all over the place :)
and a fun little harmless party prank that will have people freaking out all around you:
get two ice cubes, hold em loosely in your fists, then party and shake your hands as if you would with a samba shaker, you'll squirt water droplets all over the people around you and they will have no idea where it came from :)