Last week, amused ice skaters in New York City's Bryant Park watched as a klutzy skater suddenly transformed from a scared, stumbling novice into an expert on blades right before their eyes. Was it magic or just quick learning?

Turns out it was the work of Improv Everywhere, a group of guerilla performance artists responsible for the No Pants Subway Ride and Frozen Grand Central. The stunt -- a collaboration with the Ice Theatre of New York --delighted, eliciting smiles from the captive audience. For behind-the-scenes info and pictures, check out Improv Everywhere's site.