April 19th is National Hanging Out Day, which despite what you might think, is not about chilling out with your best buds. According to Treehugger.com, it’s day when we ignore the dryer and air dry your clothes on a clothesline outdoors. The holiday was actually founded by “clothesline activist” Alexander Lee, and is meant to promote your “right to dry” laundry outdoors, a simple, green middle finger to zoning laws, landlords and the homeowners’ associations who prohibit it. When we think of hanging out, we conjure up images of the very best nip slips. Though they’re hard to spot in “real life”, celebs are constantly spotted “letting it all hang out” thanks to the paps. On the day, we finally got to intentionally see Brooklyn Decker’s nips, we celebrate with this photo gallery of accidental nip slips.