You know those movies that run "blooper reels" during their ending credits, showing what a blast the cast and crew had making the movie?

Well, "Ocean's Twelve" (search) doesn't need said blooper reel, because if the two hours before the credits don't convince you this was anything but hard work for all involved, a few flubbed lines aren't going to do it.

And that's what makes it fun. Like the first installment, "Twelve" is ostensibly about a heist, but it soon becomes clear that's just an elaborate excuse for the remarkably big-name cast -- returning players George Clooney (search), Brad Pitt (search), Julia Roberts (search), Matt Damon (search), Elliot Gould, Bernie Mac, Andy Garcia, Don Cheadle, Carl Reiner, Casey Affleck, Scott Caan and newbies Catherine Zeta-Jones (search) and Vincent Cassel -- to romp across Europe.

"The problem with sequels," explains Clooney, "is that it's usually just a rehash of the film before. But Steven [Soderbergh, the director] had a way of saying, 'Let's mix it up and really throw these characters off.'"

Ditching the bright lights of Vegas for the subdued tones of Amsterdam, Rome and Paris, the gang has to pull off a big-time caper -- make that, big-time capers -- in order to pay back wronged casino owner Terry Benedict (Garcia), who has somehow managed to track them all down.

Things get even more complicated when a rival thief known as "The Night Fox" (French actor Cassel, perhaps best known to American audiences from the swashbuckling adventure "The Brotherhood of the Wolf" and for being the husband of "Matrix" stunner Monica Bellucci) challenges them to a "heist-off."

All this while a crafty Europol agent (Zeta-Jones) -- who has a history with Pitt's Rusty Ryan -- is hot on their trails.

"This movie was actually hatched during our press trip for the first one," says Pitt. "Our last stop was Italy. We were sitting at a restaurant after having some beautiful pasta and Steven said, 'I have an idea for the second one.' It was born there."

And newcomer Zeta-Jones seems to have had no problem fitting in with what was -- with all due respect to Roberts -- pretty much a boy's club.

"The truth is that it's just easy and it's fun," says the Welsh beauty -- even though Clooney and Pitt are renowned on-set practical jokers.

"I thought the guys didn't like me because I didn't have any jokes played on me," she says. "But I have been informed that the jokes can take up to three years to play out -- I've known George for two years now so I have a year left, I guess."

Adds Pitt: "I think the biggest joke was on Catherine because she actually thought we were making a movie."

The on-set camaraderie and the loose shooting style allowed the actors to play around with their alter egos and find new quirks and comic possibilities. Sometimes, however, the results weren't so glamorous.

"I don't know how my character ended up being such a bumbler," says newly minted action hero Damon. "I think it was a reaction to doing 'Bourne Supremacy,' and being so sick of being right in every scene. I wanted to play a guy who wasn't right that often."

But getting everyone -- and we mean everyone -- from the original back together was definitely what you would call "right."

"I got closer to everyone," admits Cheadle, "The first day we came back to work in Chicago, we all just stood around for two hours talking -- just kind of reminiscing. After a while we were like, 'Are we going to work today?'"

The close-knit crew even got a chance to stay at Clooney's house in Lake Como, Italy, during production. "It was fun," says the host himself. "We took a boat to work a lot. And Matt Damon is very clean, I will say that."

Even Roberts' much-publicized pregnancy didn't slow things down. In fact, it inspired Soderbergh to get creative -- and results in one of the most surreal, and funniest, sequences in the movie (which we're not going to spoil here. Let's just say it requires Roberts' Tess to act pregnant, and the rest you'll have to wait and see).

"I think Julia looked beautiful in the movie," says producer Jerry Weintraub, who actually worked with Frank Sinatra, Dean Martin and the rest on the original "Ocean's Eleven" back in 1960. "The comedic stuff Julia does in the film are the highlights of an already stellar career. It's going to be one of the biggest things talking about after the movie comes out."

So while the fate of a possible "Ocean's Thirteen" is still up in the air ("Who knows? I mean, we just finished 'Twelve'!" teases Weintraub), one thing is for certain: These guys know that having fun, but more importantly having that fun translate onto the big screen, requires a delicate -- one might say scientific -- balance. We leave it to Prof. Pitt to break it down for us.

"I'd like to call it work, but it's pretty automatic for us. First of all, there's a very low level of maturity among the guys. Then we've got very beautiful women around to make us look a little better. Like I said, it's pretty automatic."