When it comes to pumping out Super Bowl ads that score well with viewers, Anheuser-Busch is widely acknowledged to be the master. This year, PepsiCo has a new tactic to steal some of the brewer's limelight. The snack-and-beverage company is offering $1 million to anyone who can create a Super Bowl commercial for its Doritos tortilla chip brand that trumps all other ads in viewer rankings during the gridiron matchup. It's part of an effort to raise the stakes on a contest the company ran two years ago. By dangling a $1 million prize, it hopes to dominate the months of pregame buzz, which many public-relations and ad executives say is far more valuable than winning the myriad Super Bowl ad polls. This has become a critical way to help offset the high costs of advertising during the Super Bowl. Ad time for this season's game is selling for about $3 million for 30 seconds, up about 10% from last season.