Fast-forward to a month from now: You're sitting on the subway on a brisk January morning, and notice something strange. Why is the businessman next to you removing his pants?

You look up: A pair of teenage girls stand by the doors sans skinny jeans. And the 70-year-old woman pushing through the crowd has no outerwear covering her derriere. Most likely, these folks won't be the only ones without leggings.

The lunacy is part of Improv Everywhere's annual No Pants! Subway Ride.  It's just one of the hundred or so worldwide "missions" (as they're cheekily termed) that the group's founder Charlie Todd describes as "scenes of chaos and joy in public places."

The group came into being shortly after he moved to New York.

After graduating from the University of North Carolina at Chapel Hill, Todd was taking classes at Upright Citizens Brigade and living the life of a bored out-of-work actor. One day  in August 2001, while sitting with a friend in a West Village bar, he had an idea.

His friend would pretend to recognize him as Ben Folds (of Ben Folds Five). As his buddy acted as a surprised fan, fellow bar patrons joined in, some asking him for his autograph. "One girl even gave me her phone number," he added, chuckling.

The experience inspired him.

"I got excited about the idea of doing things in public places that are harmless and that are prankish in nature, but are about giving someone a really awesome experience," said Todd.



With friends from UCB, he created Improv Everywhere. Together they started to perform prankish improv happenings around New York City.

The missions all had one thing in common: The actors would create an off-kilter situation in a public space: They'd break out in song in a grocery store; they'd repeat a scene every five minutes in a Starbucks; they'd high-five everyone on a subway escalator. And in no cases do they break character, ever. They play everything straight.

Over eight years, the events became more elaborate.

The group staged a fake U2 concert across the street from Madison Square Garden. They choreographed a mass performance in department store windows at Union Square. They even staged a "love connection" in a taxicab traveling along Sixth Avenue.

What started as a handful of friends expanded to sometimes including hundreds of "agents." The group hit an apex with "Frozen Grand Central" in January 2008.

Over 200 agents—many of whom Todd did not know personally—gathered at Bryant Park to create a pair of five-minute freezes at New York's landmark train station. Passersby on the terminal floor turned to one another for an explanation of the scattered individuals frozen in place. Is it a protest? Is there some symbolic message or agenda? The cast provided no explanation.

"It makes people stop for a second and observe the world around them," explained Todd. "And in a way, it serves to expose a lot of new people to the art [of improv]."

Although it wasn't their intention, the group's events seem to be taking improv comedy to a new level by taking it out of the clubs and into the streets of New York.

Part of the group's ethos is to capture each mission on tape.

Uploading them to the Web, the group was able to take advantage of the rise of online video—particularly YouTube—to promote Improv Everywhere.

"I was very fortunate that YouTube was created," Todd said. "I had this opportunity to show people what I was doing outside of just text and photographs." To date, the mission has nearly 20 million views on YouTube.

Todd uses the Web extensively. He documents their missions on the group's website, ImprovEverywhere.com. Recently, they've expanded to Twitter and Facebook.

Their online presence has helped to give the group a worldwide audience, inspiring re-creations of missions overseas. "That speaks to the power of YouTube," says Todd. "You have an international audience."

In some cases, the events become a kind of political theater. Within five days of each other in April 2008, groups in Beirut, Lebanon and Tel Aviv, Israel re-created "Frozen Grand Central" at community hubs.

"There was so much hatred between the governments at least, but the populations definitely had a lot in common," Todd said.

Recently, Todd collected the group's idea in a book called "Causing a Scene: Extraordinary Pranks in Ordinary Places with Improv Everywhere" (co-written by Alex Scordelis) to inspire other groups to follow their example.

Even so, the main focus for Todd and his core group of more than two dozen "senior agents" is to continue to develop fresh ideas for pranks at home in New York City.

The group's most recent mission, "Where's Rob?," involved longtime member Rob Lathan. In the prank, Lathan wandered around a Knicks game at Madison Square Garden pretending to be lost. His castmates sat in their seats calling to him, but he pretended not to hear them. Soon, other sports fans jumped into it, shouting and chanting to get his attention.

When Lathan finally "finds" his way back to his seat, the surrounding sections erupt in applause. Little did they know it was all a setup.

"I should get lost more often," said Lathan of the joyous response. "We couldn't have asked for a better section."