Does anyone have any info about volunteer labor cooperatives?

I remember seeing a flyer for a cooperative where members posted skills or tasks that they would be willing to do in exchange for other labor. Basically volunteers would donate time/resources to eachother for projects with which they needed help. For instance one person might time for minor home repair projects in exchange for help setting up a home network. The premise was that you volunteered your time. No money exchanged hands and each member reached a mutual agreement. I am interested to find out if other communities have tried this and if so, what type of things did you do to make it a successful endeavor?