Want to bump up your bicycle mechanic skills and do some good at the same time? Volunteer at one of the nonprofits that recycle old bikes. I live in New Jersey and volunteer one afternoon each week as a bike mechanic at a nonprofit bicycle shop called the Bike Exchange (BEX). It’s a program of the Boys & Girls Clubs of America. At the BEX, we refurbish donated bikes and make them available to the public at low cost. Our inventory is whatever bikes are contributed, but we receive a surprising variety, from big-box store brands to Zebrakenko racers, Peugeot Carbolites and Nishiki Tourers.