GM, like Doritos, is also running a user-generated ad during the Super Bowl. But unlike Doritos, GM retained more control over the ad. In GM's contest, teams of college students pitched ideas for a Chevy spot. The company selected five finalists and each team then worked with a professional ad agency on a 30-second spot.

The winning ad will be announced in a prime-time special about Super Bowl ads that will air on February 2 on CBS, which is also broadcasting Super Bowl XLI on Feb. 4. This photo shows Shlomo Goltz, a student from Washington University in St. Louis, pitching his team's ad. The team is one of the five finalists.

Terry Rhadigan, director of communications for Chevrolet, said the company decided to limit its contest to college students since the automaker sees younger drivers as a key growth opportunity.

"We're trying to reach a younger demographic. We want to be relevant for younger people. Selfishly we want to endear some of these young minds to our company and to our product," Rhadigan said. GM will also air another 60-second ad for Chevy as well as a 60-second GM corporate ad during the game.