Uh oh. Your garbage disposal is broken. Time to call the plumber, and shell out for a couple hours of service, right? What if there was a different way? What if, instead of calling in a professional, you could simply call a plumbing-savvy neighbor with a bit of time on his or her hands. In return for helping out, they’d get a “time credit” to spend in the neighborhood. They could redeem it for, perhaps, a home-cooked meal, or two hours of gardening help or babysitting.