Something similar I just read:
No-pants subway rides
Every January, select New Yorkers brave the elements to participate in the No Pants Subway Ride, an event staged by the Improv Everywhere prank collective. Participants board the subway in the middle of winter sans pants, to the amusement of fellow straphangers.
This event presented the Shobha hair-removal salon with a unique opportunity to publicize its services. In January, The Manhattan salon sent a team of pants-free participants to the event in underwear proudly bearing the Shobha name.