Bicycle riders share a special sort of ingenuity (and stamina!). They're responsible for everything from generators to trailers to actual homemade rides. A few examples to peruse and enjoy:

Homemade Bicycle Generator by The Do It Yourself World

Homemade Bicycle Trailer | 200+ lb capacity by BraveTheWilds

Homemade Bicycle Generator 40v dc 100watts + by kurtscottage

HomeMade Bicycle Stand by richpin06a

My homemade bicycle by Cameron Turner