This is a fantastic initiative, conceived in San Francisco in 2005; the 2008 recently took place (September 19). It’s a day in the calendar designed at recapturing car spaces in city streets and reclaiming them for the people:
“PARK(ing) Day is a one-day, global event centered in San Francisco where artists, activists, and citizens collaborate to temporarily transform metered parking spots into“PARK(ing)” spaces: temporary public parks”.
You can find out more about Park(ing) Day at the website, and view all of the associated PR, images, and publicity generated on the Trust of Public Land site here.
There’s even an instruction manual as to how to go about setting up your own park!