(REUTERS/Lucas Jackson)

A young boy looks up at a woman with no pants on while riding in the subway system during the annual No Pants Subway Ride in New York on January 8. The event is organized by Improv Everywhere, and involves participants who strip down to their underwear as they go about their normal routine. WTF and why?

The mission started as a small prank with seven guys and has grown into an international celebration of silliness, with dozens of cities around the world participating each year. The idea behind No Pants is simple: Random passengers board a subway car at separate stops in the middle of winter without pants. The participants do not behave as if they know each other, and they all wear winter coats, hats, scarves, and gloves. The only unusual thing is their lack of pants.

There are reports from participants on the Improv Everywhere website. More photos follow, below. NSFW-ish.

No Trousers Day participants on a flashmob ride in London. (REUTERS/Chris Helgren) Read the rest