Humpday is hilarious until it comes face to face with a haunting sadness. This review, of several I read, gets to the heart of the film. It seemed to be, finally, pessimistic-- and not only about friendship. It reminded me somewhat of the conclusion of Y Tu Mama Tambien-- only less life affirming.

The question of friendship, how it should be expressed, and how maintained in the world of work, marriage, and children is as key today as ever.

Humpday

Ben and Andrew make a porno

Mark Duplass (left) and Joshua Leonard play buddies who enter a local art-porn contest. (Magnolia Pictures/AP)

By Ty Burr Globe Staff / July 24, 2009

Stop me if you’ve heard this one before. Two good friends dare each other to do each other in a homemade porn film, then try to back nervously away from the moment of truth without appearing to wimp out. “Zack and Miri Make a Porno’’ was last year’s entry, and it was reasonably mainstream: name stars, well-known director, professional camerawork, a script. “Humpday,’’ which made a solid splash at this year’s Sundance, is the mumblecore version.

I know, I know, the filmmakers lumped together under that media-inflicted label - Andrew Bujalski (“Funny Ha Ha’’), Mark and Jay Duplass (“Baghead’’), Joe Swanberg (“Hannah Takes the Stairs’’), this movie’s Lynn Shelton - just hate the term “mumblecore.’’ But it sticks because it’s useful, describing a surprisingly strict naturalist aesthetic and the bedhead attitude that goes with it. Mumblecore does away with such dreadful middle-class conceits as steady camerawork and soundtrack music, and it apes the rhythms of “real life’’ as lived by talky, self-absorbed, white 20-somethings. The characters in these movies could be Woody Allen’s slacker children, and 30 years on they’re no closer to enlightenment than he was. That’s the joke, and it’s a good one, but it’s also starting to get pretty thin.

“Humpday’’ at least serves up some caustic laughs before fizzling out. The central characters are old college buddies Ben (Mark Duplass) and Andrew (Joshua Leonard). The former is married, gainfully employed, and working with wife Anna (Alycia Delmore) on starting a family; the latter blows into Seattle from Mexico, where he claims to be working on a “community art project’’ that needs grant money, or art, or something. Ant and grasshopper, in other words, and each rankles defensively in the other’s assumed perceptions. “You’re not as Kerouac as you think you are and I’m not as picket fence as you think I am,’’ complains Ben in a rare moment of clarity.

Goaded at a soiree by a pair of artsy lesbians (omnisexuals, really; one’s played by the director), Ben and Andrew agree to enter a local art-porn contest called Humpfest with what seems to them a groundbreaking idea: two straight guys having sex. It’s a terrible idea, actually, but neither wants to be the first to admit it. “Humpday’’ nails a certain desperation lurking behind the complacency of the Starbucks generation - a fear of being insensitive, uncool, non-progressive. One’s parents, in other words. Ben and Andrew can only prove their New Age macho by sleeping with each other.

So they stall and double down while Ben leaks details about the upcoming filming to his wife (Delmore’s face registers wonderful nano-shifts of exasperation and horror). Those conversations are the funniest part of “Humpday,’’ with the characters doing their level best to sound mature while squirming like toddlers faced with a plate of liver. After a while, you realize this could be an old “Honeymooners’’ plot sexed up for the Naughty Aughties, Ralph and Ed concocting a ka-razy plan they have to hide from Alice. “The Honeymooners’’ never featured rubber penises, though. To my knowledge.

For all the talk, the movie’s rather chaste: That’s its point and its limitation. Real pain has no place in mumblecore: Andrew resembles a younger version of Will Oldham’s hippie burnout in 2006’s far superior “Old Joy,’’ but Shelton acknowledges the raging sadness behind the character’s eyes without ever exploring it. “Humpday’’ just wrings every uncomfortable laugh from its premise then shudders to a halt: cut, end credits. I can think of about five nervier places this film could have gone, but that would work against the self-imposed passive-aggressiveness at the heart of the genre - the idea that meaning something, anything, would be a sellout.