We have been tossing around the idea of hooking up one of our bikes to our grain mill. The mill is electric, but it also has a hand-crank option. The hand-crank is physically very HARD...so with a few pulleys, we could do it by bike easy enough.

From there we could charge up batteries or other items...or even crank the agitator on a washing machine....

Some day, anyway.

ETA - our first order of business would be to hook the cream separator to the bike. It would be much easier to maintain a constant speed using a bike than cranking by hand (I would imagine).