In the old days neighbors pooled their collective muscle to help one another erect barns and other structures. The practice has waned in modern times (except maybe among community-minded groups like the Amish), but there are signs of a small resurgence. The residents of Benton County, Oregon, for example, got together recently and built a barn at the fairgrounds powered by solar roof panels. The Worchester Community Action Council in Massachusetts runs weatherization barnraisers where volunteers come to a home or building and install energy-efficiency upgrades. And in Arizona, the Watershed Management Group uses the same model to help homeowners install water-saving features in their homes and on their properties.