Ben and Andrew go way back, but can they go all the way? That's the question posed in Humpday, Lynn Shelton's droll and startlingly funny portrait of men testing the limits of friendship while negotiating the pressure to appear cool.

The college pals haven't seen each other much since Ben got married to Anna and Andrew decamped Seattle for Mexico and other points south.

Ben's a Jason Bateman type, clean-shaven and tucked in to pleated trousers. He likes the rhythm and comfort of marriage, knowing what will happen tomorrow, next week, and next year. At this very nanosecond, he and Anna are working on the next generation. ("We officially removed the goalie and are free-kicking," Ben explains.)

Andrew, on the other hand, is an Owen Wilson type, shaggy, free-spirited, and untucked in jeans that have seen a lot of mileage. He likes making it up as he goes along.

These textbook examples of bourgeois and bohemian manhood are viewed in the decidedly non-textbook film in which Ben (Mark Duplass) and Andrew (Joshua Leonard) each secretly wishes he were more like the other.

Wouldn't it be great not to be tied down, thinks Ben when he wanders into a Dionysian party to which Andrew has scored an invite. Wouldn't it be great to have a regular home, thinks Andrew as he shares a nightcap with the initially wary Anna (Alycia Delmore).

At that anything-goes soiree, where Andrew flirts with a fetching bisexual artist (writer/director Shelton) and her girlfriend, Ben looks on silently, ever amazed by his pal's social savoir faire.

When the old friends, by now soused, hear the hostess speak of a Seattle film contest, Humpfest, they propose to make a heterosexual "man-on-man, non-gay porn."

Is it a dare? A joke? Giving voice to unconscious desire? Will Anna freak when she finds out?

Shelton's sympathetic gaze penetrates past the bear hugs, back-slapping, and bravado (much of it improvised by the appealing actors) to see men anxious before the sexual buffet.

In Ben world, where the pressure to procreate has replaced sexual pleasure, Andrew's freedom looks mighty attractive. On Planet Andrew, where he is invited to be part of a threesome with two bisexual women and suddenly feels superfluous, Ben's commitment to one partner looks good.

While at times the improvisational dialogue sounds like audio filler, the three leads are poignant and perceptive. Likewise Shelton's film, considerably more complex than those "bros will be bros" comedies of male bonding.

Maybe manhood is something most keenly seen from the outside, for Shelton powerfully channels both the haha comedy and the human comedy. Much to their surprise, both Ben and Andrew are boxers guys, and the fact that both sport navy plaid underwear may be a tip-off that they are more alike than not.EndText

Contact movie critic Carrie Rickey at 215-854-5402. Read her blog, "Flickgrrl," at http://www.philly.com/philly/blogs/flickgrrl/.