There's no denying that it was a very good weekend at the box office. DreamWorks Animation's The Croods opened with $43.64 million. FilmDistrict's Olympus Has Fallen debuted in second place with $30.37 million -- nearly twice what it was expected to earn. And Disney's Oz The Great and Powerful remained powerful in its third week with $21.57 million. And yet. The overall box office was down once again from a year ago when The Hunger Games arrived on the scene with $152 million in box-office receipts. The difference added to the year-to-date deficit. Ticket sales are down 13 percent from a year ago, while attendance is off 14 percent. Reporting on the weekend figures, Monday's New York Times, while observing that the weekend's results may have given studios hope that a dismal box-office stretch was behind them, signs still point to the fact that moviegoing in the United States and Canada remains deeply troubled.