Is Build Your Own Gotcha Gadgets a science kit or the ultimate prank book? This hi-tech hijinks kit helps you build gadgets to set traps, play games, and trick your friends and family. Build the basic Gadget, then follow the simple instructions to wire a motion sensor, door alarm, light sensor, or push-button device--along the way, you'll learn the principles of electronic circuitry. After you program your gadget with one of four funny "gotcha" sounds, you can foil late-night raids on the 'fridge or booby trap your little brother's lunch bag. It?s science in the service of immaturity -- a veritable science fair exhibit with the soul of a whoopee cushion. 9-volt battery not included.