On Friday, September 21, parking will be tough on Hamra Street in Beirut, Lebanon. And good luck finding a spot in Downtown Toronto or Austin, Texas. Parking will be tight in Downtown Vegas, too, thanks to PARK(ing) Day, an international “open-source experiment in reclaiming public space.”

What does that mean? In cities across the world, organizations and individuals will take over parking spots, transforming them into personalized mini-parks for as long as they can afford to pay the meter. Photos from last year show how diverse the installations can be: a makeshift stage in Dallas, a faux crime scene in Brisbane, a Twister board in Phoenix. Your spot could be a four square court, a chalk art gallery or a putting green. But even PARK(ing) comes with some strict rules.

According to the official event website, Rebar—the Bay Area art and design group that started the holiday in 2005—must be given inventor credit on all signage, and participants are limited to two posters per installation, no more than 11 by 17 inches each. Which makes me wonder if PARK(ing) officers will be enforcing the rules. Or if perhaps it’s time for Free PARK(ing) Day, an open-source experiment in reclaiming public space ... without weird restrictions.