27. The Black Eyed Peas (2011)
The worst. Just the worst. Watching at the time, you instantly knew you were witnessing something magical and special – like seeing a unicorn cough up blood. The Black Eyed Peas had light-up robot suits. Cool! Sorta! They did their version of "I've Had the Time of My Life." Not so cool! Usher looked like he wanted to hide. Then the tragic words: "Ladies and gentlemen . . . the one and only . . . Slash!" Oh Slash, poor Slash – dueting with Fergie to "Sweet Child o' Mine." How did this happen? This was the same Super Bowl where Christina Aguilera did her memorable interpretation of the National Anthem, so yeah, music had a rough day. So did Steelers fans.