Time Out says
Forget all your stress and adult worries as you (softly) pummel strangers. At New York’s annual International Pillow Fight Day, participants turn Washington Square Park into the city’s biggest bedroom. The rules: don't hit too hard, avoid smashing cameras and leave down pillows at home (feathers create a mess). If you prefer to leave your pillow in the safety of your apartment, stop by Mattress Firm's NoHo location and grab one in exchange for a $5 donation to the Mattress Firm Foster Kids program.