These organizations exist on about one-third of the city's residential blocks. They bring neighbors together as volunteers to improve the local quality of life. They bridge the private and public domains with collective action that benefits the entire community. They are keeping streets clean, fighting drugs, tutoring children, organizing recreation programs, planting community gardens, and conducting other activities. These groups have several characteristics. They are geographically based, volunteer-driven, and locally initiated. In addition, they are empowering, small and informal, and multipurpose and flexible. In addition, they come into being to solve specific problems and focus on getting things done. At their best, they transform isolated individuals into public citizens and generate both tangible and intangible common goods. Photographs.