After classes, Sally Peach, a student at the Massachusetts Institute of Technology, has a long list of to-dos. She wants to hit the gym, tackle schoolwork, and, as captain of an intramural soccer team and member of a campus health advocacy program, she has plenty of e-mail to respond to every evening.“Though I know I am being productive, it feels like a complete waste of time to sit there and do just [e-mail replies],” says Ms. Peach.
So, once she arrives at the gym, Peach makes a beeline for a special stationary bike that has a laptop built into the front. The computer is not plugged in. There is an empty space where the battery once fit. But when Peach starts pedaling, the computer fires up. Her spinning workout powers the laptop – and lets her cross off two tasks at once.