If you listen to Warner Bros’ version of the back story behind The Hangover, this weekend’s #1 film and the third highest R-rated comedy opening, it sounds so very simple like a class in Hit Moviemaking 101. (And I’m assured the total pay of all three lead actors doesn’t even add up to the perk package that Will Ferrell had on Land of The Lost.) So Hangover spec script is penned by the screenwriting team of Jon Lucas and Scott Moore and gets to director Todd Phillips, who reads the screenplay and loves it and has a deal at the studio. BenderSpink’s Chris Bender then approaches Warner Bros SVP of production Greg Silverman with the script and director already in place. Jeff Robinov, who has been/is a fan of Phillips, makes the deal. “It was one of those things that simply came together — a script, a director, and all the ducks were in a row,” a WB source tells me.

Oh really? Well, here’s what I first thought was the full and complete story of how The Hangover got made. (And why wasn’t any of the following mentioned in Sunday’s New York Times story about New Line and Warner Bros?? Now people are coming out of the woodwork to tell me there’s still more missing info. I’ll keep updating. But, for now, here’s what I know:

It all started with Chris Bender who heard the story of how his Hollywood friend went mysteriously missing from his bachelor party in Las Vegas. The pal (photo, right) was film producer Tripp Vinson (The Guardian, The Number 23, and now the Red Dawn remake) who in 2002 was engaged to marry Endeavor motion picture lit agent Adriana Alberghetti. Like always happens, the real facts don’t quite match up with the movie. There was no wedding scheduled that same weekend. Instead, the bachelor party was held months earlier. It consisted of 30 guys booked into the Hard Rock Hotel for a wild night of partying at a succession of Vegas restaurants, clubs and strip joints.

“I remember being a drunken fool, as you’re supposed to do at your bachelor party, and having a really good time with all my friends,” Vinson told me. “But then I remember being a mess. And when people are fucked up, crazy shit happens.” That’s when Tripp went missing from his bash. Even now, all Vinson knows is, “I got separated from my friends, and I blacked out. And when I was revived, I was in a strip club being threatened with a very, very large bill I was supposed to pay. It was not a fun experience at the time, but it made for a funny story.”

Bender thought it would make a great movie. So he kicked the idea around with the Four Christmases writing team of Lucas and Moore who had a good working relationship with New Line. So did Bender who produced both New Line pics Monster-In-Law and Just Friends, on which the writing pair did some uncredited work. It turned out that New Line really wanted a Bachelor Party-set-in-Las Vegas movie, and SVP/COO Richard Brener wanted to buy the pitch for $750,000. Everyone was excited — but then New Line boss Bob Shaye threw up a roadblock: he said he’d only buy it if the movie could be called, What Happens In Vegas. But the phrase that relaunched Sin City proved a nightmare to purchase since so many people claimed to have come up with it. When New Line couldn’t clear the title, Shaye didn’t buy the film. (In 2008, 20th Century Fox used that title. Clearly, it had better lawyers.)

The writers went off and wrote. But by then they wanted a huge raise for the project. New Line passed at that price (as did every other studio) — especially with 2 other bachelor party movies being fast-tracked at Universal. So then the writers and BenderSpink decided to spec it out with the understanding that New Line would get first crack. But when the spec was finished, CAA agent Gregory McKnight attached Old School director Todd Phillips to the project and slipped it to Warner Bros because Phillips had a first-look deal there. At the time, Phillips’ star wasn’t very high: he’d stumbled with Starsky & Hutch at Warner Bros, and been replaced as the director of Borat. But Warner Bros nonetheless bought the spec script pre-emptively. (My sources claim McKnight sold the script without Bender. And it was only after Bender showed WB lawyers his email exchanges with Lucas-Moore that the studio finally agreed he’d helped develop the concept.)

Then again, back in 2003, the same Greg Silverman bought a pitch from Mark Perez for The Afterparty, in which a young man enjoys his Las Vegas bachelor party so much he can’t remember anything about it. Then, as he and his fiancee make last-minute preparations for their big day, the strange characters he befriended during his lost weekend — including a chicken and a tiger — begin to make surprise appearances. Silverman was to oversee the project. Jamie Kennedy was attached.

Meanwhile, under Silverman’s supervision, Phillips and Jeremy Gerelick (The Break Up) did a rewrite described to me as vast of The Hangover inserting the the baby, the tiger, Mike Tyson, the gangster, the cop car, and more. (Some say the duo was “robbed” of a credit by the WGA arbitration.) Bender after his armtwisting got a fee and an executive producer credit as a “make-good”. New Line was left holding its dick. And now Phillips has the sequel underway.

As for Tripp Vinson, he wasn’t involved with the movie at all. “I wasn’t even aware of it. Once the spec went out, I became aware of it. I know they embellished the story.” Nor did Warner Bros buy his life rights: he laughed when I told him a good lawyer could secure a trust fund for his kid. As for Chris Bender, this is the 3rd time he’s taken a real-life Hollywood producer’s life story and put it on the big screen. You may already know this, but Chris Bender claims American Pie is based on his own high school experiences (Jason Biggs plays Bender), and that’s why Bender received a co-producer credit on the pic. (However, others maintain that American Pie was based on the life of Adam Herz, the writer. The original title was East Great Falls High, which was the high school Herz went to. Bender helped Herz develop it.) And Just Friends also was supposedly based on Bender’s life and he got a producer credit on that, too.

Meanwhile, Warner Bros studio chairman Alan Horn is still trying to claim to the Los Angeles Times that all the credit for this movie goes to his studio, and to his little-liked No. 2, Warner Bros. Pictures Group President Jeff Robinov. “It was Jeff and his troops who got Todd Phillips involved [No, that was CAA], allowed the movie to be R-rated [It was always R-rated], and let Todd make the movie he wanted to make [Because Robinov can’t do comedy to save his life, and at best it was exec Greg Silverman.] He clearly knew what he was doing.” Statements like this prove the old adage that you always know a mogul’s lying because his lips are moving.