Super Bowl or "The Big Game"?
Super Bowl XLV is this Sunday, February 6. You've probably heard or seen advertisements promoting the Big Game at restaurants, sales on groceries and TV specials for Game Day, as well as sweepstakes and contests related to the Big Game. The Big Game, or Game Day, is of course referring to the Super Bowl but there are strict rules about who can use the trademarked term "Super Bowl." See NFL's terms and conditions (2). The only advertisers permitted to use the term Super Bowl pay a licensing fee and receive authorization from the NFL to use the term.
Of course, there are instances where the NFL cannot prohibit references to the Super Bowl, including news stories and informational blogs like this one.
You can read a variety of court opinions that deal with the NFL and trademarks when browsing these search results from Google Scholar. You can also read about football-related cases in last year's Super Bowl post.