As a keen snowboarder, Damon Collins, executive creative director of Rainey Kelly Campbell Roalfe/Y&R, enjoyed making the title sequence for the BBC's Vancouver Winter Olympicscoverage. The result was unusually stark and bleak: "It's a truth that you have to be pretty hardcore to compete in the games," he said, "so we wanted to go dark."

Another Olympic title sequence, for the Beijing games, won RKCR/Y&R a Bafta in 2009—the first time the award (the U.K. equivalent of an Oscar) has been presented to an advertising agency—for a film co-created with Damon Albarn and Jamie Hewlett of Gorillaz.

Mr. Collins is fond of collaboration. He worked closely with Penguin Books to create "A Crocodile for Billy," a children's story that taught Lloyds TSB customers about the benefits of saving more and spending less. For Bacardi, he started a record label and signed British dance duo Groove Armada, for whom the agency created a pop promo, CD artwork and an online sharing system.

Rainey Kelly went hardcore again for the government's anti-knife-crime push. "We didn't deliberately shock," Mr. Collins said, "but we had two clear messages: You will get hurt, and you will go to jail. We were talking to people who thought that, if your thumb was cut off, it would grow back. ... So they are less like ads and more like documentaries."

The agency spawned a pop-up version of itself last summer, RKCR/Y&R Local, offering "fresh ads served daily" free to neighboring businesses. Takers included a tattoo parlor, a surf/skate/snow shop and a band called Dead on TV.

See the rest of the 2010 Creativity 50 here.