This Brilliant Door Prank Will Terrify Your Friends

Sure, anyone can pull off the "salt in the sugar shaker" prank, but it takes true ingenuity to pull of something like this: a door-triggered air horn. Here come the heart attacks!

The supplies are minimal. Duct tape. Air horn. An inexhaustible capacity for sadism. Park this prank in your friend's bedroom/dorm/office, wait for the EEEEEEENHHHHHHHHHHHHHHHH and smile. [9Gag -- Thanks Nicko!]