Thor: The Dark World has scored a hammer blow on the North American box office for the second week in a row. The superhero film took in $38.4 million (GBP25.6 million) over the weekend (15-17Nov13) to beat out new release The Best Man Holiday, which earned $30.6 million (GBP20.4 million) over the same period. The Thor sequel also grossed $52.5 million (GBP35 million) overseas, bringing its global haul to $479.8 million (GBP319.9 million). Last Vegas, which features Morgan Freeman, Kevin Kline, Robert De Niro and Michael Douglas as aged pals enjoying a wild weekend in Sin City, comes in third with $8.85 million (GBP5.9 million) and animated film Free Birds takes fourth place with $8.3 million (GBP5.5 million). Johnny Knoxville's comedy Bad Grandpa rounds out the top five. Meanwhile, George Clooney and Sandra Bullock are celebrating after learning their science fiction thriller Gravity has hit the $500 million (GBP333.3 million) mark at the worldwide box office.