Saw one of these commuting on a downtown DC street this morning. Went by too fast to get a picture.
It looked at first glance like a Smart car, but then I realized it had bike wheels. You pedal it and it also has an electric motor. You can exert as much effort as you like, and they suggest letting the electric motor do the work in the morning so you arrive at work fresh and clean, and pedal on the way home, only using the motor to help on hills.
Organic Transit ELF