Brad Pitt's big fat Greek comedy, er, I mean epic, Troy, topped the box office with a good-but-not-great $45.6 million. Insiders speculate that the $200-million flick likely lost some of its opening-weekend audience to Saturday's NBA Playoff game between the Los Angeles Lakers and the San Antonio Spurs. Another theory behind the so-so gross: Word quickly spread that the film was as campy as a Clay Aiken concert. Last week's No. 1 movie, Van Helsing, slipped to No. 2 with $20.1 million — a monstrous 61-percent tumble from its $51.8-million bow.