"During a two-month period last year, seven civic coalitions in New York neighborhoods like East Harlem and the South Bronx got permits from the city to close certain local streets to traffic for designated periods of time - say, between 10 a.m. and 3 p.m. on a summer weekday. Working with the police and other city agencies, they re-designated the areas as temporary "play streets," encouraging neighborhood children to use them for exercise and offering a range of free games, athletic activities and coaching.
Call them pop-up playgrounds.
The experiment was successful. According to Karen Lee of the Department of Health and Mental Hygiene, which helped oversee the project, data collected from the sites indicates that families visited local play streets for one to two and a half hours on average - time that many would have otherwise spent inside, according to a majority of the parents surveyed."
12 pop-up playgrounds have been built this year.