Tropic Thunder debuted as the No. 1 movie at the box office this weekend, earning $26 million and knocking The Dark Knight from five consecutive weekends at top . Despite protests and boycotts about the use of blackface, the combat satire starring Robert Downey Jr. , Ben Stiller and Jack Black has earned $37 million since opening on Wednesday. Though The Dark Knight slipped to No. 2 with a weekend gross of $16.8 million, the flick is now the second-highest-grossing film in history. ...