LEGO-enthusiast Michael Gasperi's Mindstorms-based "Galvanic Skin Response Sensor" may be just the DIY option you need to liven up your next party. Basically a set of foil-lined velcro strips attached by 9V wire to an RCX control brick, Gasperi's lie detector works on the principal that people sweat more when they're fibbing, so his device measures the skin's electrical resistance of whomever's getting grilled. One word of caution if you decide to build one of these on your own, make sure to keep your subject alive by powering your detector from batteries and not deadly AC.