Laughs will tear us apart?

There’s a moment, about a third of the way into The Hangover, when the drolly uncool oaf played by Zach Galifianakis tries to supply his companions with a little context for the adventure they’re having. “…It’s got Ted Danson, and Magnum, P.I., and that Jewish actor…” he starts to say, in a throwaway line, before the pressing action of the scene interrupts him. He never gets to finish his thought. He doesn’t have to. It is this moment, perhaps more than any other, that holds the key to The Hangover’s excellence.

If anyone knows the reason why a lovely couple shouldn’t be married…well, it’s one of these morons. Zach Galifianakis, Ed Helms and Bradley Cooper find a tiger and lose a groom (Justin Bartha, second from right) in The Hangover.

To understand it will require two things. First, an allowance that the word “excellence” may be used to describe a comedy about three groomsmen (Bradley Cooper, Galifianakis and Ed Helms) getting so wrecked at a Vegas bachelor party that they lose their memories and their groom (Justin Bartha). Second, the willingness to appreciate a film that makes short work of acknowledging its conceptual similarity to Three Men and a Baby.

There are other movie references, too, all equally offhand. With its plot-driven mystery, menace and urgency, the whole thing might even be reckoned as a classic film-noir scenario, except that it’s been retooled for the comedy of dumbassery.

That’s how The Hangover’s easygoing self-awareness works. It knows perfectly well how cheap it is, and doesn’t let that or anything else slow it down. Nimble, fun, funny, adventurously over the top, and not too tedious or completely lame, it’s just the opposite of how its own trailer makes it seem.

So, what the hell did happen last night? Where did that chicken come from, or the tiger, or the baby, or the angry naked Asian man (Ken Jeong) in the trunk? How did Stu lose a tooth, and gain the favor of a perky stripper (Heather Graham)? What’s become of Doug, who’s supposed to be getting married today?

To these questions, perhaps the only satisfactory answer can be a magnanimous reminder from Mike Tyson: “We all do dumb shit when we’re fucked up.” That, and an outrageous closing-credits slideshow well worth waiting for.

What a relief and delight to discover that The Hangover doesn’t suck, given its origin as a screenplay by Jon Lucas and Scott Moore, the team responsible most recently for Ghosts of Girlfriends Past, which did. What a difference a good director (Old School’s Todd Phillips) and cast makes.

Being the best big-screen Bradley Cooper vehicle to date may not sound like much, but that’s sort of why it is. This is a man who had begun to register, if at all, as little more than a soulless, low-res Ralph Fiennes facsimile, so he’s an inspired choice to play what one critic wisely called the core trio’s “alpha douche.”

Helms’ buttoned-down dentist, the unlikeliest of bachelor partiers, is just as good. And then, of course, there’s Galifianakis. As one character observes, possibly on our behalf, “He’s actually kind of funny.” Or, as another puts it later, “It’s funny ’cause he’s fat!”

Well, it is.