The Smartsuit Pro is a form-fitting jumpsuit equipped with 19 gyroscopic sensors. These detect the angle, momentum and position of your head, arms, legs and torso, then feed that information into a central hub on your lower back. The data can either be recorded locally on the hub's hard drive or streamed directly to a computer using WiFi. You'll get about 6 hours of use out of the suit before it needs to be recharged, though its batteries can easily be hot-swapped.
Given its $2500 price point, the Smartsuit Pro is geared primarily towards independent filmmakers and game developers. I was recently afforded a chance to don the suit and transform myself into a digital anthropomorphic frog. It went about as well as you'd expect.
The Smartsuit is essentially a snug jumpsuit with a headband and spandex hand and foot cuffs. Getting into the suit is easy enough (even if the one I tried was a size too small): just slide your feet in and pull the suit up around you. I would not recommend wearing street clothes underneath because, even though the suit itself is breathable, using it over multiple layers and jumping around still means you're going to get sweaty, and fast. Well not actually jumping -- that's one of two motions that the system doesn't handle yet. The other is laying flat on your back as that blocks the hub's WiFi signal, though that's not an issue if you're recording locally.