The New York City subway can be a strange place, and it will only get stranger when passengers take off their pants. The group known as Improve Everywhere has organized the 12th annual "No Pants Subway Ride" in the dead of winter: Jan. 13.

The event is scheduled to take place from 3-6 p.m. on Sunday in New York City, and participants are encouraged to ride the subway trains in their underpants. Organizers said that about 60 cities so far are expected to participate.

“The turnout was great last year and the after party was one of the biggest we have had,” said event organizer, James Cobalt, about the 2012 event, according to BostInno. “This will be the sixth year in a row we will have this in Boston, and it’s really exciting.”

Potential coordinators can register their area for the event. Participating cities will be listed on Facebook and the Improve Everywhere website.

The Facebook page for the New York City "No Pants Subway Ride 2013" event has more than 3,000 people signed up as of today. The event page also links to the No Pants Official Afterparty for NYC participants; “A pantless party at Bar 13 on 13th Street on the 13th day of 2013!” reads the description. The cheeky party will have a $10 cover and drink specials “for the pantless.”

Participating cities include: Adelaide, Amsterdam, Ann Arbor, Atlanta, Austin, Barcelona, Bangalore, Berlin, Boston, Brisbane, Buenos Aires, Calgary, Chicago, Cleveland, Copenhagen, Dallas, Hamburg, Helsinki, Houston, Istanbul, Jerusalem, Las Vegas, Lisbon, Ljubljana, London, Los Angeles, Madrid, Manchester, Melbourne, Mexico City, Miami, Milan, Minneapolis, Munich, New York, Oslo, Paris, Phoenix, Portland, Porto, Prague, Prescott, Salt Lake City, San Diego, San Francisco, Santiago, Seattle, Sofia [Bulgaria], St. Louis, Stockholm, Sydney, Tel Aviv, Torino, Toronto, Valencia, Vancouver, Vienna, Warsaw, Washington, DC and Zürich.

Improve Everywhere has a promotional video uploaded to YouTube of the 2012 No Pants Subway Ride in New York City. Subway patrons are seen gathering and removing their pants as unaware riders look on in disbelief.

The flash mob organizers also posted a series of videos from each year's "No Pants Subway Ride," along with a testimonial video from the perspective of a woman who witnessed the first pantless event in 2002.