Unfortunately, the biting keyboard is as old as the 1920's version of Burroughs' Interzone. What about helium filled umbrellas that grab ahold of the hand and lift the user off the ground 10 or 12 feet and then lets go! People could get hurt, but no more so than with exploding toilets. I don't think anyone would die. There has to be a happy medium between practical joke and murder, don't you think?