Serious answer? It's a proving ground for Madison Avenue, and lots of advertising campaigns launch during the game (or pre-game). The slots cost millions because there are millions of Asses In Chairs who are more or less captive aside from the occassional beer/piss run. In recent years it's become fashionable to watch the game for the commercials, which are generally longer than the standard 30-second spot, have more celebrity appearances, and are higher-concept, with smarter/sexier/more tear-jerking content. In theory.