The Rock flexed his box-office biceps over the weekend, as the wrestler-turned-actor's new action comedy The Rundown debuted at No. 1 with $18.5 million. Diane Lane's romance Under the Tuscan Sun opened in second place with a surprisingly strong $9.41 million, edging out last weekend's top flick Underworld (No. 3 with $9.4 million). Further down the chart, Drew Barrymore and Ben Stiller's new black comedy Duplex was (as expected) a big ol' money pit. The film grossed a weak $4.6 million for sixth place.