If you’re looking to show off those sweet undies you got from Santa to someone besides your significant other or your cat, you’ll get your chance when Improv Everywhere’s annual prank invades the NYC rails. There are meeting spots in Manhattan, Brooklyn and Queens; from there, the horde takes to the subway in their skivvies.

Astoria: Meet at Hoyt Playground
Brooklyn: Meet by the Old Stone House
Downtown Manhattan: Meet at Foley Square
Lower East Side: Meet at Sarah Roosevelt Park on Houston
Queens: Meet at the Unisphere in Flushing Meadows Park
Uptown Manhattan: Meet at the Great Hill in Central Park
Williamsburg / Bushwick: Meet at Maria Hernandez Park

Be at your meeting spot by