This guy built a generator powered by a homemade recumbent bike.  It seems to be a mixture of proof-of-concept relating to alternative energy, and a fun way to use up old junk parts.   He manages to get a peak electrical output of 203 Watts @ 550RPM at the generator (my wild-ass guess is the generator is about 40-50% efficient) and decides that 6 or 7 cents per KW/H from the power company is a "fantastic value." 

--posted by roy