Don't be alarmed if you get on the METRO this afternoon and there are a bunch of people without their pants on. 

Today is the annual 'No Pants on Metro Day'

[Image via NBC Washington]

Improv Everywhere (the group behind the day) posted this on their Facebook page

"District of Columbia laws are very subjective. Try not to wear anything more revealing than “PG-13”, such as a typical women's bikini bottom or a men’s Speedo. When in doubt, wear two pairs of underwear. Take this as an opportunity to show off your style (or lack there of)!

All garments should be clean! We are sitting down on seats that other passengers on metro will use. Please be considerate.

Interested pants-less parties should convene at 2 p.m. Sunday at Hancock Park outside the L’Enfant Metro station (7th and C streets SW)."