07/09/2012 09:35 am ET Updated Sep 08, 2012

Movie Review: The Do-Deca-Pentathalon

Boys will be boys. Always.

Testosterone may not confer eternal youth on the male of the species, but it does enforce perpetual juvenile traits that can never truly be bred out of men.

These come to the fore in Jay and Mark Duplass' The Do-Deca-Pentathalon. A shaggy, basic tale of fraternal jealousy writ large, DDP is funny, if not deep, an amiable, sometimes aggressively funny film that occasionally dawdles. Yet there are obviously funny people at work here, who understand the fine line between hysteria and hysterical.

It's Mark's birthday, so the dumpy, balding Mark (Steve Zissis) takes his wife Stephanie (Jennifer Lafleur) and preteen son home to his mother's house for the occasion. Conspicuously not invited: Mark's brother Jeremy (Mark Kelly), apparently a source of stress and friction for Mark -- and everyone around them when they get together.

The brothers seem not to have spoken in years and, when Jeremy turns up unexpectedly for the weekend, we learn why. The two of them have always been neurotically competitive, so much so that, Mark eventually reveals, Mark's been in therapy because he gave himself a heart problem stressing over it.

How bad was it? Jeremy brings up the Do-Deca-Pentathalon, a 25-event personal Olympics in which the two of them had challenged each other as teens. The final score was 12-12; the conclusion of the final event, a breath-holding competition, was inconclusive because their father pulled Mark out of the water because he thought he was drowning.

Mark won't bite on Jeremy's taunts -- until a late-night encounter with Jeremy sets him off. But he's promised Jennifer he's not going to be baited into old behavior patterns - so they have to figure out a way to blaze through 25 events during the weekend without her finding out.

The Duplasses have an easy-going, no-frills style here and, in Kelly and Zissis, a pair of guys who look like the kind of neighborhood types with hidden skills and obvious weaknesses that you'd see trying to win a game of "Horse" against each other in the driveway. This movie understands the way a friendly contest can turn deadly serious, the way something trivial suddenly takes on life-changing importance -- at least in that moment -- all out of proportion to the rest of actual life.

There's not a lot to The Do-Deca-Pentathalon and yet it never drags. And, more often than you'd expect, it makes you laugh. It may not set the world on fire, but it will amuse you without boring you -- a quality that is becoming rarer and rarer.

Find more reviews, interviews and commentary on my website.