Photos: Improv Everywhere's public hijinks

Improv Everywhere is a New York-based group that for years has been pulling off pranks around the city. Generally, the group settles on a theme, brings together a number of "agents" and then perpetrates the prank. Once it has taken place, the group puts video and photos of the prank online. A video of one of the group's pranks, in which hundreds of people at Grand Central Station in Manhattan simultaneously "froze," was watched more than 9 million times on YouTube.

Here, the group gathers for a prank at a Manhattan Best Buy. The idea was to have dozens of "agents" show up dressed in blue shirts and khaki pants so they looked like Best Buy employees.