San Francisco's Fast Park Movement
"[W]hat makes these parks truly remarkable are the fast-track way in which they were created-a highly visible experiment in urban planning, where the community can test-drive the design and provide input before it becomes permanent. It took only a few months to get sign-off on the plaza design and three days to install it. Design services were supplied pro-bono by the firm Public Architecture, labor was provided by the Department of Public Works, and all materials were donated. The bollards are cardboard concrete molds, lined with plastic and planted with palms and flowers, and the asphalt was painted tan to distinguish it from the street."
The city's planning department has its eye on 25-30 more sites for possible park conversion.