Donât be surprised if you see a few bare legs this weekend while riding the MBTA. Bostonâs seventh annual âNo Pants Subway Rideâ will take place on Sunday, Jan. 12 on subway trains across the Hub. Created by Improv Everywhere in New York City in 2002, this annual event now occurs each January in cities around the world.

Bostonâs version of the event will be hosted by BostonSOS, which -- according to their Facebook page -- touts themselves as a âunique social network that organizes and promotes guerrilla theater, urban adventures, interactive street art, offbeat events, and charitable living through unusual tactics.â

The premise of the âNo Pants Subway Rideâ is simple: Participants board subway trains throughout the city wearing their normal winter gear and then drop their pants as unsuspecting passengers look on.

BostonSOS has details about the event, including where participants should meet, on their âNo Pants Subway Rideâ event page on Facebook, which you can view here. Each group can be tracked throughout the day using a designated Twitter hashtag.

The after party will take place at McGreevy's at 911 Boylston Street. Participants under 21 will be admitted, and those over 21 will receive a bracelet at the door to purchase alcoholic beverages. There is no cover for this event.

If youâd like to participate in the âNo Pants Subway Rideâ or learn more about the event, visit BostonSOSâs âNo Pants Subway Rideâ event page on Facebook.