Las Vegas the fifth character in comedy ‘Hangover’

It's not a trip to Vegas if you don't do things you'd never do at home.

Get plastered and trash a high-roller suite? Check.

Hit the blackjack tables in desperation, hoping to fatten up your empty wallet? No surprise there.

But picking up a Metro patrol car at valet parking? Having a run-in with a naked, hopping-mad gangster who pops out of a car trunk? Stealing a tiger from Mike Tyson?

No wonder the guys in "The Hangover" have world-class headaches.

Opening in theaters today, "The Hangover" stands poised to break out as the summer's hottest R-rated comedy, as four guys hit Glitter City for a bachelor party so wild no one can remember anything the morning after -- including the future groom's whereabouts.

Which forces our hung-over heroes to try and track down the missing bridegroom by following the few clues they can find, including two unexpected guests in their demolished Caesars Palace suite: a cute little baby and a great big tiger.

When screenwriters Jon Lucas and Scott Moore ("Ghosts of Girlfriends Past," "Four Christmases") first wrote what became "The Hangover," that tiger belonged to Siegfried & Roy.

"That felt more organic," Lucas and Moore admitted during a recent promotional junket (at Caesars Palace, where else?) for "The Hangover."

But director Todd Phillips had a different suggestion for the tiger's only-in-Vegas owner: Mike Tyson.

During filming, Tyson himself "was really cool and chill," says Ed Helms ("The Office"), who plays Stu, the movie's resident nerd. (Unlike the tiger, Helms adds, who "was scary as" a deleted expletive.)

Clearly, Phillips "has no boundaries," Helms notes, citing one scene in which his character (and his buddies) wind up at the business end of a stun gun -- and Phillips wanted the actors to do the scene themselves.

"You can't tase me -- I'm an actor!" Helms told his director. "I can act like I'm getting tased!"

And Heather Graham, who plays Jade, a heart-of-gold hooker (are there any other kind?), cites a blackjack sequence -- filmed at the Riviera -- in which her character was supposed to collapse backward from the table in a phony faint.

"Todd kept saying, 'You don't need that many pads' " to break your fall, Graham recalls.

Yet Phillips also encouraged the performers to "let us add to our characters," notes Zach Galifianakis, who also appeared in last summer's wild-Vegas-night comedy, "What Happens in Vegas." This time around, Galifianakis portrays the childlike Alan, the groom's future brother-in-law, who desperately wants to join the already established circle of friends.

Anyone recovering from this "Hangover" has definitely bonded for life -- including the movie's cast and creators, who discussed their sometimes uneasy adjustment to Neon Nirvana during more than a month's location work last fall.

"It's hard to be in Vegas," Phillips says.

Not filming in Las Vegas, because "the city, the police and the casinos make it easy," the director says. Despite the fact that "you're surrounded by crowds who are busy gambling and don't care about the movie."

No, it's the nature of Las Vegas itself -- at least as portrayed in the movie.

"One of the things I like about the movie is that you're seeing Vegas in the daytime -- and it's not particularly nice looking in the daytime," Phillips says, likening the effect to "a stripper without her makeup. ... You think, 'Wait a minute, this isn't how it looks at night.' "

Overall, Las Vegas "is sort of the fifth character in the movie," says Bradley Cooper, who portrays Phil, the groom's college buddy. (Phil's married -- but you'd never know if from the way he cuts loose.)

"What this town does to you," Cooper continues, "you feel like you're in a sort of crazy world."

To Graham, "there's something in the air," she says, describing Las Vegas as "almost a New York vibe gone insane. It's hard to fall asleep here -- there are all these things you feel you should be doing."

And for Justin Bartha, bridegroom-to-be Doug Billings, Las Vegas "still has that same old smell of despair and that wonderful melange" of tourists "trying to get rich quick and going back home with their tail between their legs."

"The Hangover's" bachelor-partying tourists just want to find Doug and get him to his wedding on time. Failing that, they'll settle for getting out of town alive.

Because the characters can't remember what happened and must retrace their steps to jog their memories, they discover the awful truth as the audience does.

"Like a good horror movie, you don't see the monster," Moore explains.

After all, Lucas adds, "the biggest cliche is to show the party itself. With certain experiences" -- including "The Hangover's" crazed comic complications -- "you really have to be there."

Contact reporter Carol Cling at ccling@reviewjournal.com or 702-383-0272.