The term "Super Bowl" is a trademark owned by the National Football League, and it is protected very aggressively. What does that mean? The biggest no-no of all is to use the term "Super Bowl" in any advertising or promotional announcements that are not sanctioned by the NFL. This prohibition includes sweepstakes and contests as well. Advertisers pay high licensing fees to the NFL for the right to use the term "Super Bowl" in their advertising. You will almost certainly hear from the NFL's attorneys if you use the term in advertising without explicit authorization from the NFL. So no "Super Bowl sales" in your ads - and don't refer to your station as the "Super Bowl Authority" in your promotional statements. These restrictions explain why you often hear it referred to as "The Big Game." But this restriction does not mean you cannot utter the words on air under any circumstances.
There is a court-created trademark concept known as "nominative fair use." Under this concept, trademarks can be used when necessary under certain conditions. First, the mark must not be readily identifiable in any other way. For example, you do not have to refer to the Pittsburgh Steelers as "the professional football team from Pittsburgh." Secondly, you can only use the mark to the extent necessary to identify it. Repeated gratuitous use would cross the line - for instance if you repeatedly state that your station is "the place to hear everything about the Super Bowl." And third, you cannot do anything to suggest a false connection or sponsorship arrangement. What does this really mean? It means that DJs can use the term "Super Bowl" editorially in discussing the game on air (but not in a way to imply that the station has a connection to the game, or not in a repeated way analogous to a station slogan or positioning statement). It means that news stories about the game can refer to the "Super Bowl." The NFL will not consider such uses to be trademark infringement so long as the use is reasonable. In fact, from an editorial perspective, the NFL appreciates some hype about the game to attract viewers and general consumer interest in the game.
Another dangerous activity is sponsoring a large screen viewing of the Super Bowl. Even if you refer to it as the "Big Game" to avoid trademark issues, a public large screen display of the game violates the NFL's copyright in the telecast of the game. You specifically want to avoid showing the game to an audience on a screen larger than 55 inches diagonally, or on any screen if viewers have to pay to watch the game.
If you follow these guidelines, you should not have any legal problems relating to the NFL's ownership of both trademark and copyright rights in the Super Bowl. Enjoy the Big Game!