Draco Malfoy and the slimy kids of Slytherin couldn’t have wreaked more damage on Harry Potter than a bunch of commando guinea pigs did to Harry Potter and the Half-Blood Prince this weekend. G-Force, the live-action and CGI action comedy, earned $32.2 million this weekend at the North American box office, besting the $30 million take of the sixth Potter film, according to the usual movie-studio estimates of the weekend frame. Final numbers are posted Monday.