You could earn $0.35 per hour with a very fit person on bicycle power generator (which exist, and output 125-400W depending on how fast you pedal). That assumes

You could earn $0.35 per hour with a very fit person on bicycle power generator (which exist, and output 125-400W depending on how fast you pedal). That assumes current Bitcoin mining difficulty and block size, $439 US/BTC conversion rate, and a 300GH/s hash rate from a Butterfly Labs Monarch BPU 300C -- you can power one of these and the computer it's in from one person on the bike. Unfortunately, at that rate, it would take half a year of non-stop pedalling just to pay for the Bitcoin mining hardware. If you mine with an old leftover PC instead of dedicated ASIC, you'll earn fractional pennies instead of dimes.