WHAT IF the famous moment in Superbad had gone further, with Jonah Hill pushing something more tumid than his finger at something more intimate than Michael Cera's nose? Or if the massage at the end of Old Joy had gone for the famous happy ending? Lynn Shelton's odd sitcom Humpday starts where bromance comedy leaves off. In Seattle, the very married Ben (Mark Duplass) is scheduling his lovemaking with his sweet, placid and equally plump wife, Anna (Alycia Delmore). Sessions are timed for optimum egg delivery: "We've removed the goalie," he says. At 2 in the morning on the eve of one procreation session, the doorbell rings; it's Ben's dear old friend Andrew (Joshua Leonard), who is dropping in without calling first.

Andrew has just arrived from southern Mexico. He is a raffish, bearded Pan disturbing this domestic bliss; for the next couple of days, he crashes in what's going to be the baby's room. Later, he picks up a girl and heads to her party house, a place named "Dionysus." Ben wanders in for a fast drink and doesn't wander out until 3am. During a night of drinking, smoking and trance music, a woman mentions an underground porn film festival. Trying to think of something extreme enough to win, the two lads decide that a film of very straight men having gay sex would be a winner. "Beyond gay," they call it. Because Ben wants his pal to know that he isn't a bourgeois sellout, he won't back down during the hung-over day after. But he is naturally too scared to tell Anna about his plan. Some farcical misunderstandings lead up to a fateful rendezvous at the Holiday Inn.

The wooliness of Humpday adds to the appeal; it also adds to the film's downfall. Watching one half-muffed line after another dissolving into nervous laughter, I thought that the film's idea had been shaped, maybe just not the scenes. But later, the ideas seem elusive, too. Andrew is supposedly just spinning his wheels by teaching art in Chiapas, but why is that not worthwhile? Making this porn is going to be the art project that proves he can finish something he started. Ben's participation will give him the cred to finally tell his buddy, "You're not as Kerouac as you think you are." And Anna's permission will prove that she's not Betty Crocker either.

It's unclear what role lust plays in all of this. Eventually, watching the two men grapple, get queasy and call for time-outs, made me wonder: had director Shelton thought of Humpday as a statement about how so much porn is made under conditions of almost total sexual disinterestedness? It seems to be a little more straightlaced than that, even. If Humpday has earned more attention than most mumblecore, maybe it's because the film ultimately doesn't disturb the status quo in anything--either male friendships or marriages. The most composed and affectionate shots are of monogamous bliss--the images of Anna and Ben's home. The movie is a bait and switch on the level of James Toback's similar Two Girls and a Guy. In a world full of brave and interesting homemade porn--art, smut or what have you--Humpday is not as Jack Kerouac as it thinks it is.

HUMPDAY (R; 95 min.), directed and written by Lynn Shelton, photographed by Benjamin Kasulke and starring Mark Duplass and Joshua Leonard, opens Friday.

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