According to the manufacturer, the Xdream is the "first indoor fitness product that accurately simulates the experience of riding outdoors." Basically, the bike thrusts you into a virtual world via the attached computer screen. As you ride, the full experience on the screen is translated to the equipment—right down to the track surfaces and conditions. Plus, it utilizes a full range of muscles in the upper body and lower body, which makes for a more complete workout. Pricing isn't advertised, but expect it to set you back many thousands of dollars. Alternatively, you could grab a bike and actually go outside. [Xdream]