here's simply a google seach results page for
pedal power generator:
pedal power generator - Google Search
I remember reading in "Home Power" magazine about 10 years ago or more a fellow from Davis, CA, USA, wired up a wheelchair motor backwards to be a (pedal-powered) generator.
I'm surprised that the human-powered TV noted by akashic in post #4 (Amy no pedal? Amy no see cartoons) hasn't caught on for gyms and home exercise set-ups. Good motivation there.