I don't really have anything great. In high school one time we picked up a kid's Geo Metro and set it down between two telephone poles so that there was maybe a foot of space between each bumper and each pole. Took the guy like 20 minutes of forward/reverse/turning a couple inches at a time before he had enough room to get out. At school a few times we've sent out emails when another coach left their desktop open. Nothing gets a faster response than a mass email sent to a district of 3K people saying "Hey I can't use my Cowboys tickets this weekend- anybody want them?" One time in college my wife had a big exam and I changed her clock and shook her awake when it was time to get ready, only a quick glance at her clock made her think she had already missed the exam. Anyway...like I said....nothing great. Anybody have anything better? Oh yeah, the worst prank... When I was in high school, somebody got the idea from something they had heard about their older sibling at another school doing. At graduation, everybody took a marble and handed it to the principal during the handshake. The thought being that after so many people did it, he'd have nowhere to put them. Problem was, there were only 70 people in my graduating class. And that fits pretty easily into a couple of pockets.