The No Pants Bart Ride, an annual Bay Area tradition celebrating its 13th year, returns Sunday with hundreds of riders showing off their best boxers, briefs and undies before letting it all hang out on the streets of SF.

The party is scheduled to arrive at Montgomery Bart station at about 1:20pm before heading to Yerba Buena Gardens and likely nearby bars.

The rules are simple for those who would like to attend:

1) Participants must be willing to take pants off on subway (before you board)

2) They must be able to keep a straight face about it

3) Have at least $10 for the BART/MUNI rides and some extra for bar/etc.

(or a clipper)

4) Please no nudity (there are children on BART, don’t want to tempt the police)

More details. Highlights from previous events from the SF Station archive: