Updated

Despite the bracing cold, the Internet is heating up in preparation for the 9th annual No-Pants Subway Ride.

The brainchild of improve comedy troupe Improv Everywhere, the No Pants Subway Ride is happening today in New York City -- and already in 16 countries worldwide. In the event, riders gather at pre-selected locations, casually remove their trousers and ride en masse to a central location, all the while acting as if nothing out of the ordinary were taking place.

As with other popular Internet memes, such as the bed jumping phenomenon and other assorted “flash mobs," most of the planning for this type of event takes place on the Internet.

For the No-Pants Subway Ride, a Facebook event page lets would-be participants RSVP, Improv Everywhere’s site links to Google Maps for meeting points and the #nopants “hashtag” on Twitter allows people to follow current comments regarding preparations for the event, which is scheduled to last from 3pm to 5:30pm.

And Twitpic, a Web site that hosts photographs for Twitter users, has a handful of pictures of pantless riders already. As of 2:15pm, the Facebook Event has 8,629 confirmed guests -- though that doesn’t mean everyone will ride pantless, of course.

Improv Everywhere’s Web site offers useful advice to participants:

“As soon as the doors shut at the stop before yours, stand up and take your pants off and put them in your backpack. If you’d like to use a briefcase, purse, grocery bag, or whatever instead of a backpack that’s fine too. If anyone asks you why you’ve removed your pants, tell them that they were “getting uncomfortable” (or something along those lines.)”

The requirements for participating, according to Improv Everywhere, are quite simple:

1) Willing to take pants off on subway
2) Able to keep a straight face about it

After all, the event is intended to entertain, not offend, explains Improv Everywhere.

Here is the video from last year's event.