National Treasure: Book of Secrets starring Nicolas Cage took over the top spot at the weekend box office, grossing $45.5 million (all figures US). I Am Legend was pushed to second with an additional $34.2 million, making it an “Over $100 million” box office earner in just two weekends. Alvin and the Chipmunks dropped from second to third with $29 million, while the new movie Charlie Wilson’s War, starring Tom Hanks, debuted in fourth place with $9.6 million. Sweeney Todd, opening in limited release, managed to make it into the top five with $9.4 million. It’s scheduled to open wide in the new year.