Just call him -- Novie Mac? Novak Djokovic added to his repertoire of memorable impersonations Monday night, channeling his inner John McEnroe in front of a roaring crowd at the U.S. Open. The fourth-seeded Serb's YouTube-worthy impressions of Maria Sharapova, Rafael Nadal and others -- which earned him the nickname of "Court Jester" -- haven't always been so well-received. More...