Samuel "Jack" Hairston III looks like your doting grandpa, if the old man had a soft spot for bikes and migrant workers. Jack has white hair, a handle-bar mustache, and a broad smile. At his shop, workers and volunteers take old bikes and parts, repair them, and resell them to support Jack's charity. The nonprofit donates hundreds of used bikes and helmets to needy kids — many of whom are the children of migrant workers in the area — every Christmas. This is a worthy cause no matter how you slice it, but getting a new set of wheels for your money is a bonus. When you buy a bike from Jack, you get a collection of seemingly mismatched parts — perhaps a Raleigh frame with a clunky chain and barefoot pedals. But each machine runs well, and each one has a story: a past and a future bright with the promise of a good deed.