There's less than a week left till we see the Baltimore Ravens and San Francisco 49ers duke it out in Super Bowl XLVII, but also Beyonce, Kelly Rowland and Michelle Williams will be taking the stage together for the first time in seven years during the year's largest football game's halftime show. But while we wait, let's take a look back at the past. Remember the controversy surrounding Janet Jackson's nipple? Or the time M.I.A. flipped the bird on live TV? Here are five of our favorite halftime show performances.