Pillow fight

Wikipedia:  A flash mob (or flashmob) is a group of people who assemble suddenly in a public place, perform an unusual and seemingly pointless act for a brief time, then quickly disperse, often for the purposes of entertainment, satire, and artistic expression. Flash mobs are organized via telecommunications, social media, or viral emails.

Saturday, April 5, 1pm - Flash mob pillow fight in Sergels Torg, Stockholm