The first No Pants Subway Ride took place in 2002 with seven riders and has grown since then.
In 2009 over 1,200 people participated in New York and over 3,500 participated this year.
The New York event is organized by a collective calledImprov Everywhere.
Here are some photos taken on Sunday, January 9, 2011.
The temperature outside was 29 degrees Fahrenheit.
