I like the scenes from "the office" when the guy puts other peoples stuff in Jello. Like the stapler, etc. they look for it, open the drawer and there it is in a block of jello. that's priceless. you could also give him a blue screen of death screensaver if he has a pc at his desk. all these of course you know would get you in serious trouble IF YOU GOT CAUGHT. so don't. don't let anybody else in on it either.