Conservation of angular momentum for fun and fitness!!

I had never heard of this thing until I stumbled upon it today. It's been around for several years. Looks like a lot of fun. I want one.

Trikke (pronounced trike) three-wheeled cambering vehicles are human powered machines that utilize Trikke Tech’s patented 3CV technology to allow a rider to propel a chainless, pedal-less device forward without ever touching foot to ground. This elegantly simple construct provides a stable 3-point platform that leans into the turn with the rider while all three wheels remain in contact with the ground. A rider may reach speeds of up to 18 mph on flat ground, ride 50 miles in one day, and climb the steepest of hills (with practice!).

Trikke’s design allows the rider to naturally engage his entire body throughout the ride. Legs are active for balancing and shock-absorption and arms punch for power-thrusts and hang on for stability and control. The Trikke 3-wheeler allows you, the rider, to feel the miracle of your own body and mind working in graceful unison. The bi-products of the ride are joy, health, fitness and a renewed appreciation for yourself and your life.

Trikke cambering vehicles allow a rider to utilize a fundamental physics principle known as the Conservation of Angular Momentum. While traveling on a slalom-like path, a rider moves his center of gravity (his mass) from left to right (for example) while leaning the vehicle into a right turn; this movement of the rider’s mass is towards the center of the turn, thus decreasing the radius of an imaginary circle which is formed around the center point of the rider’s turn. This movement of mass to the center of the circle acts in the same way that an ice-skater increases her velocity if she pulls in her arms (decreasing her radius) while she is spinning on the ice.
Because of the vehicle’s design, a rider can learn to maximize the velocity generated from making each turn and then transfer that momentum into the next turn, and so on and so on. Propulsion can be so effortless that it feels like magic, or as strenuous as a full-blown sprint. Your choice.

In the simplest of terms, you rock & roll to make a cambering vehicle go. An experienced rider uses the entire body in a gracefully coordinated motion that leans the vehicle into each turn and transfers the momentum of each forward thrust into the next turn and the next. A trikke ride combines the utility of human powered transportation with the thrill of carving deep surf and ski style turns. Like in other carving sports, everyone develops their own unique, individual riding style. Each ride becomes a personal expression session.

Click the image below for more info. Be aware, these are so popular that the manufacturer can barely keep up.