World's Largest Human Power Plant

"When students at Texas State University exercise, they keep themselves physically fit and their university fiscally fit. Following the example of a few other institutions, the university has installed 30 elliptical machines that generate electricity—making it the world’s largest human power plant—which can be fed into the campus grid. A thirty minute workout, for instance, could generate enough energy to power a desktop computer for a half-hour. The machines cost around $20,000 to install, but could pay for themselves in seven or eight years."

- From Harvard Government Innovators Network