It's been years since Eric Kallman and Craig Allen teamed up on what would be their first assignment together: Skittles. That work from TBWA/Chiat/Day, New York, proved to be seminal, and Messrs. Kallman and Allen say they're still known as the "Skittles guys." Still, in the years since, the pair has moved on to Wieden & Kennedy, Portland, Ore., where they've created breakthrough spots for CareerBuilder and Old Spice.

"We were lucky to come in on two great accounts," said Mr. Allen, who joined the agency along with Mr. Kallman in 2008. "It's fun to write in the Old Spice tone of voice, and it works really well with our sense of humor."

Their sense of humor—easy, quirky, somewhat sarcastic—is a key component to their successful partnership. "We respect each other's sense of humor and sensibility. We trust each other," Mr. Kallman said. "When we both laugh hard at something ... we think it's something working out." Such was the case with the recent The Man Your Man Could Smell Like work for Old Spice. The spot, which features a chiseled actor with a baritone voice in a bathroom, on a boat and on a horse, has garnered more than 3 million views on YouTube.

"We were working on ideas that would appeal to men and women, and we stumbled upon the beginning, and it made us laugh," Mr. Kallman said. "The idea that ended up being the spot was one of many. It was a good idea to us but not a surefire standout."

"It's such an odd business," added Mr. Allen. "You never know what will work or not."

See the rest of the 2010 Creativity 50 here.