I use a standing bike: http://www.elliptigo.com/ http://www.elliptigo.com/. It's more of an elliptical trainer on wheels than an actual bike. They're pretty a

I use a standing bike: http://www.elliptigo.com/ http://www.elliptigo.com/. It's more of an elliptical trainer on wheels than an actual bike. They're pretty awesome, and a much better workout than a road bike. If you don't want to actually cycle around with it, an adapter transforms it into a stationary trainer.