It's easy to burn off a few calories when you go to the gym - but you're also using plenty of power in the process. With all the treadmills, exercise bikes, elliptical machines, and flat-screen TVs they contain, gyms are some of the biggest energy suckers around.
Not the Green Microgym, a new business in Portland, Oregon. This gym, which launched a week ago, boasts an opposite approach: The gym's human users actually power the equipment through their exercise.
Any movement on the gym's stationary bikes contributes power to a set of batteries, which are used to generate electricity for the TV and stereo. Though the energy output is still relatively small, the gym's owner, Adam Boesel, is dreaming of bigger, greener things. "Our goal is to someday create 100 percent of the electricity we use in the gym," he told ABC News. "The short-term goal is to get all of the electricity we can out of the machines."