*Thanks to the rare southern snowstorm that hit Atlanta last weekend, B.o.B. ended up rapping about his beloved Atlanta Falcons playing the Green Bay Packers in a Pepsi commercial for this weekend’s NFL playoffs.

“Yeah, it was crazy, man,” B.o.B told Billboard during a break from a recording session. “You know Atlanta is not too fond of snow. When it snows here, everybody runs out and buys everything in the stores. And there’s no snowplows here, so you’re kind of just on your own.”

All of which meant that the 22-year old rap phenom, just nominated for five Grammy awards, was called in at the last minute to help out his snowbound friend and mentor Outkast’s legendary Big Boi, when he couldn’t record the vocal part for the football-themed hip-hop track.

“There’s still ice all over Atlanta,” a snowed-in Big Boi said.  “I’ve been in my house since Sunday, so B.o.B. went in and did my song.”  The cut is based around “Night Night,” a song  from Big Boi’s acclaimed “Sir Lucious Left Foot: The Son of Chico Dusty” LP that already featured B.o.B.

The re-cut song, recorded for this weekend’s playoff game, is part of a larger promotion between the NFL and the launch of Pepsi’s new Pepsi MAX soft drink that debuted during last weekend’s upset-filled wildcard weekend. The Pepsi MAX NFL Audible videos, as they are officially known, feature tracks by Big Boi — which began airing last week  — B.o.B, Talib Kweli, Lupe Fiasco and rap upstart Nick Javas, some of which can be seen on NFL.com.

“The videos will air through the Super Bowl and during the 2011 fall season,” said Frank Cooper, Pepsi’s chief consumer engagement officer.  The company, Cooper explained, is trying to redefine brand marketing by promoting their product indirectly. “The most important thing is to not to talk about the product, but to engage consumers with a meaningful brand experience.”

To wit, Cooper hired the New-York-based promotional company Cornerstone, which has a history of creating successful urban marketing campaigns, to do the creative on the Pepsi MAX NFL campaign.

“We chose the artists through a definitive criteria,” said Cornerstone founder Rob Stone, “that included having to fit the aesthetic of Pepsi from an artistic/creative view point and be able to deliver on the energy and spirit of the NFL.” This meant that in addition to booking high-profile rappers, Cornerstone enlisted graffiti artists ArtBattles, break dancers from Dance Stylez Entertainment and Brooklyn-based interactive media firm Hudson Dusters to direct the segments.

Also appearing in one of the spots is Talib Kweli, a rapper better known for his social-political messages (and whose new album “Rainbow Gutters” on Javotti Meda/3D records drops Jan. 25). The soft-sell of the product in the ads suited him perfectly: Kweli had no reservations rapping about his hometown team the Jets (who face a Herculean challenge this weekend in going up against the heavily-favored New England Patriots), but that’s as far as he wanted to go.

“To be honest, I would not have done a commercial where I was rapping about how good a soft drink tastes,” Kweli says, “That’s just not something I’m interested in.”