The 12th and 15th world champions played a pair of exhibition games, and as a happy surprise for fans of Anatoly Karpov, he drew both and if anything had slightly the better of things. (That said, even if Anand was playing seriously, I don't think he was using anything real in the opening.) You can read about the event, see the games, and hear (or try to hear) a long interview with Karpov, here.