Entertainment

ZACK & MIRI’S XXXCELLENT ADVENTURE

KEVIN Smith has always had a firm grasp on the “dirty” part of “dirty joke.” Now he’s got the joke part down too, and “Zack and Miri Make a Porno” is the funniest movie of Smith’s I’ve seen. It’s “When Harry Did Sally.”

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Zack (Seth Rogen, who is almost incapable of being unfunny) and Miri (the always reliable Elizabeth Banks) are two longtime friends who live together in slacker squalor in Pittsburgh, where Zack works at a Starbucks-like coffee shop. (Gosh, why wouldn’t Starbucks want its logo on this film?) They haven’t paid their bills in so long that their heat and lights go off. But they get both back, a little – by burning their unpaid bills.

This setup is pretty far from plausible; women who look like Banks don’t go hungry (although men who look like Rogen do). And the vigorous use of words that begin with “mother” and end with “ucking” by everyone, even by Indian coffee-shop managers, is a bit of a stretch, as is Miri’s telling a guy she has just re-met, “Don’t thank me, just f – – k me.”

But the point is to do (heh, heh – I said “do”) a parody of a chick flick with unrestrained fratty language that makes “Knocked Up” look prudish.

After a few dull bits at the beginning, things get roaring along. At a dismal class reunion, where Zack asks an old classmate for a little sex favor in the girls’ locker room (the look of daring to hope that crosses Rogen’s face as he does this bit is priceless) and the pair meet a gay porn star and his boyfriend (“So, you guys suck each other’s

c – – – s, huh?”), an idea begins to form. Soon, Zack is turning to Miri, taking her trembling hand in his and saying, “Will you have sex with me on camera for money?”

That seems to be their only option (when told he could be a waiter, Zack says, “Look at me. No one wants me around their food”), so Zack enlists his co-worker (the increasingly hilarious Craig Robinson of “The Office” and “Pineapple Express”) as producer and starts putting together a porno called “Star Whores.” Zack is Hung Solo, and you don’t want to know what’s hidden behind one of those metal flaps on R2-Teabag.

Things don’t go so well. “I just wanted to see some free t – – – ies,” says the Robinson character, in a moment of eloquence. “But there’s no such thing as free t – – – ies.”

The movie actually has a plot, with reversals of fortune and references to earlier beats. And though the outline of the story is the basic when-will-these-two-kids-notice-they’re-perfect-for-each-other romcom situation, the limitless raunch of this raun-com freshens everything up. Even a poo scene is pretty funny (and extremely disgusting), because it’s been properly set up.

Gone are the lengthy monologues from previous Smith films in which he “dazzles” (i.e. bores) us with his musings on religion or pop culture. The characters play off each other instead of delivering stand-up routines. And Robinson – whose character has been married to a woman he has known since kindergarten – is even funnier than Rogen, practically rotting from backed-up manly fluids. Somebody get this man a leading role, stat.

kylesmith@nypost.com