The brainchild of two MIT grad students, the idea here is to use the kinetic energy of humans in crowded urban settings, such as from that of trains or concerts. The energy from people sitting, walking, or jumping would be transformed into electricity that could be used to power signs and other devices. As a test case that was performed at an Italian train site, the students did a demo where the weight of person sitting on a stool caused a flywheel to spin, thus powering a dynamo that in turn powered four LEDs.
One idea is that walking would depress a sub-flooring system comprised of blocks that would move in response. The slippage of the blocks against each other would be converted into electricity via the same process as that of a dynamo. Because a human step can only power two 60 watt lightbulbs for a second, this concept is best applied to a crowd, where over 28,527 steps can produce enough power for a moving train for one second. With enough steps, say 84,152,203, one can power the launch of a space shuttle.
For more on the progam, including pictures, visit MIT's School of Architecture and Planning website.