Jerry Weintraub smelled a rat. It was 1 a.m. and the producer had just returned from a long night of stopping traffic and keeping curious fans at bay on the Las Vegas set of his latest project, Ocean's 11 -- the all-star remake of the 1960 Rat Pack casino-heist flick featuring George Clooney, Brad Pitt, Matt Damon and Julia Roberts -- to find a gooey coat of Vaseline on every doorknob in his suite at the Bellagio hotel. Arming himself with a baseball bat, Weintraub stormed down the hall, rapped on the door of Roberts's suite and bellowed his summons: "Where the hell is Clooney?"
As Roberts feigned sleepy innocence, Weintraub searched her room. Then, hearing a door slam, he swung around to see Clooney and Damon hightailing it down the hall. On another night, Clooney rigged a bucket of water over Roberts's door -- only to soak a hapless bellman who entered first. "The pranks here," sighs Weintraub, "are akin to Animal House."
As he approaches his 40th birthday on May 6, there's no question that George Clooney still likes to have his fun. "He's not immature, but he hasn't quite grown up yet," says Walter Bernstein, who wrote the screenplay for Fail Safe, the classic Cold War thriller Clooney reproduced as a live TV drama last year. "There's still something unformed about him." Julianna Margulies, his friend and former ER costar, has noticed too. "George," she says, "is a grown-up with a kid's heart."