The annual No Pants Subway Ride celebrated it 10th year Sunday thanks to a New York-based group of urban pranksters. It started as a small prank with just seven guys riding the subway without pants on and evolved into more than 5,000 "pants-less" people riding subways in 44 cities around the world, according to organizers.
People of all shapes and sizes shed their pants from Mexico City to New York City to the City (as in San Francisco).
The Bay Area-version started at the Powell BART station.
The premise of the event is simple: ride BART and/or Muni with no pants, and play it cool. They apparently did just that, because there were no reports of pantless mayhem on the San Francisco police blotters.
It was flash-mob like event to say the least. You can see the set up in the below YouTube clip.