At Velocity Coop we offer basic and advanced classes to the public. The Basic class is basically learning to adjust everything on your own bike, the Advanced class gets into rebuilding hubs, bottom brackets, installing headsets, etc. Coop volunteers have the option to take or audit the class.
We also have " Stripper Night". Several times a year some of our donated bikes that either can't be repaired or aren't worth repairing really start piling up. We get some beer,pizza and invite volunteers in for an evening of stripping these bikes for parts. Not only is this a great bonding experience it also give new members a chance to learn how to use almost every tool in the shop - removing wheels, headsets, forks, cranks, even pulling freehub bodies and axles off bent wheels. They learn how bikes are put together even if it is sort of in reverse, what tools do what and what all the parts are called. Not a bad way to start learning and if they do something wrong its no big deal.