Improv Everywhere's No Pants Subway Ride took over the NYC subway (slide show)

It's a good thing the polar vortex had passed through New York City before the weekend; we can't imagine how participants in this year's No Pants Subway Ride would have fared in below-freezing temps. But it was a downright balmy 45 degrees yesterday, and so thousands of brave folks stripped down to their underthings for Improv Everywhere's annual prank.

RECOMMENDED: The No Pants Subway Ride

Riders dropped trou on various subway lines, although at this point, we're guessing that most people weren't that surprised by the sight of bare legs and silly underoos during their afternoon commute. Participants converged at Union Square for a celebration before moving to Greenwich Village Country Club for an after-party. Fun times.

Click through the slide show above for shots from the festivities. Improv Everywhere also got its own photos of the event, and captured some video; check that out below.