The "WAVE Street Surfboard" is a frightening two-wheeled device intended to give you several vectors onto which you may through the air towards a wall. Like a skateboard, the WAVE is meant for use on land. Unlike a skateboard, it has only two wheels, the better to make deep slices into turns, more like a surf or snowboard. It also has a thoughtful wide rear and foredeck, the better to place my fat, whimpering ass on as I careen wildly down a hill. There's no way I would ever stand up on that thing.
The reviews on Sports Authority's site are generally positive, although most warn it has a steep (but short) learning curve and a tendency to chew through wheels fairly quickly. The WAVE is available for $100 (plus monthly health insurance payments).