Except for the many millions in paychecks they're getting for Ocean's Thirteen
, you'd never even know these guys were working. Since Brad Pitt
, George Clooney
, Matt Damon
and pals reteamed in Las Vegas to film scenes for the third of their Rat Pack-style heist capers, "it's been like coming back from summer vacation and being with your friends," says a set source. "Just guys out there having fun." With help from one gal: Ellen Barkin (taking over from Julia Roberts
and Catherine Zeta-Jones
) will inject estrogen into the movie, due out next summer. Though Clooney and Barkin took in the Cirque du Soleil show Love
together Aug. 6, after-hours Vegas carousing has been minimal. "They have a great time working together," says another source, "but they're on the set at 5:30 in the morning."