Writer-director Adam McKay's third, proudly stupid comedy lacks sharp, satirical specificity of ANCHORMAN: THE LEGEND OF RON BURGUNDY (newscasters) and TALLEDEGA NIGHTS (NASCAR), but has something that manages to hold it all together: The inspired pairing of TALLEDEGA's Will Ferrell and John C. Reilly, two actors smart enough to play dumb and make it work. It's the story of a lovely lady named Nancy Huff (Mary Steenburgen), who was busy raising two boys on her own, of whom never really grew up. Obnoxious Derek (Adam Scott) became a successful private helicopter leasing agent, but his older brother, 39-year-old Brennan (Ferrell), couldn't even hold down at job at the local PetSmart and still lives with his widowed mom. Meanwhile, divorced Dr. Robert Doback (Richard Jenkins) is busy with Dale (Reilly), a 40-year-old college drop-out with a sense of entitlement who also never sufficiently matured enough to move out and get a life. One might think two guys like Brennan and Dale would have a lot in common, but when Nancy and Robert marry and decide to move into the Doback household, all hell breaks loose. Possessive towards his mother and angry about the upheaval in his coddled life, Brennan declares his hatred for Dale, insists up coldly calling his new step-father "Mr. Doback" and screws around with Dale's precious drum kit even after being told he must never, ever lay a finger on it. Dale, pissed about having to share his room with his new step-brother and his father with the woman he simply calls Nancy, Dale threatens Brennan's life. But they wind up bonding over a common enemy -- Derek, who's convinced Robert to sell his house and fulfill his dream of sailing around the world, even if means kicking Dale and Brennan out of the nest -- and when Dale punches Derek in the face, he and Brennan realize they're truly brothers. The joke is pretty slim: Grown men behaving like spoiled kids, manipulating and terrorizing their parents as only children can. But what's hateful in a child of nine can be kind of funny in a 40-year-old, particularly when he's wearing a Pablo Cruise T-shirt. Oddly enough, the film's greatest virtue is that aside from a short speech at the end about holding on to your childhood dreams, it refuses to be anything more than unabashedly ridiculous. Even when it unexpectedly turns into THE PARENT TRAP, it knows better than to start taking itself seriously. And with Reilly and Ferrell rapping to a song called "Boats 'n' Hos," destroying their house while sleepwalking in their underwear and burying each other alive in the backyard, how could it?