ElliptiGO - It's a cross between an elliptical machine and a bike.

From the description page:

What is the ElliptiGO elliptical bicycle?
At its core, the ElliptiGO 8S is a fitness device that emulates running outdoors without the associated impact. It was designed by runners to be the ideal low-impact substitute for running. We believe it is the ideal cross-training device for healthy runners and the best replacement for running for injured runners. It delivers an exercise experience that is closer to running than anything else available today.

Who is the ElliptiGO for?
The ElliptiGO has some unique characteristics that make it a great solution for a wide variety of people. Obviously, running is near and dear to our hearts, and the ElliptiGO was designed in particular for cross-training and injured runners. However, most of our customers are not runners. They are people who want a comfortable, fun, efficient, low-impact, and weight-bearing exercise that they can enjoy outdoors. The ElliptiGO delivers on each of these conditions in a way that no other device can. As a result, our customers range from hard core cyclists and elite athletes to recreational riders just looking to get fit. It truly enables a customizable experience, enabling you to challenge yourself as much or as little as you’d like.

Watch the ElliptiGO in action:
http://www.elliptigo.com/