"Step Brothers": Downright dumb and crude and, darn it, funny

What's an appropriate descriptor for the alliance of Will Ferrell, Adam McKay and Judd Apatow?

Because the respective co-star, director and producer of "Anchorman," "Talladega Nights" and now "Step Brothers" belong to an upper echelon in raunchy comedy that strives to make adults laugh as though they were kids, "brainless trust" might not be too far off the mark. After all, coming up with stuff so stupid it's hilarious requires serious thought.

In a favorite if overly familiar formula for the Ferrell/McKay/Apatow crowd, "Step Brothers" takes the task at face value by giving middle-age men the attributes of little boys. It doesn't rank high in the lowbrow-comedy genre that has produced legitimately smart entries such as "The 40-Year-Old Virgin" or "Knocked Up" (both directed by Apatow), but it does succeed as a token contender by delivering real laughs at the expense of intelligence and decency.

A big bonus for all the uncultured gaggery comes from Ferrell's give and take with the versatile John C. Reilly. This dummy duo gives their all in creating an extended sketch that imagines the arrested development of 40-year-olds suffering sibling rivalry after their single parents marry, with everyone sharing the same house.

Ferrell and Reilly have an easy sidekick charm, whether they're staring each other down, beating each other up or ecstatically discovering they're better friends than real brothers or even run-of-the-mill soul mates.

Their earlier pairing in "Talladega Nights" made terrific use of timing that sprung effortlessly out of Ferrell's fish-eyed egotism and Reilly's goofy vacancy. This time their mutual dimness gets an equal and more elemental workout as they go to great lengths to out-stupid each other in the guise of the Two Stooges.

Once the flimsy script has the situation established, the movie is content to follow the shtick. This is not too far removed from "Dumb and Dumber" territory, but a lot of it is irredeemably funny, including the zombielike trances Ferrell and Reilly enter as man-boy sleepwalkers.

A sequence that documents their foray into the real world of job hunting says as much about improvisational rapport between skilled entertainers as it does about the bliss of maintaining a shared fantasy.

Unfortunately, there's an overarching level of inanity that often makes the larger context feel like something that must be endured. As the newly coupled stepparents, the movie asks Richard Jenkins and Mary Steenburgen to be silly, sensible and foul-mouthed in equal measure, and neither actor can fully commit to the particular need at hand.

Like many of its ilk, "Step Brothers" strives so hard to maintain a crudeness quotient that some of the more overt vulgarity comes across as forced and feeble. A piece of male anatomy that Ben Stiller made famous in "There's Something About Mary" gets a return close-up here. That it's entirely gratuitous is probably more to the good for those already going nuts with laughter.

Ferrell, McKay and Apatow have shown us before that understatement can be plenty funny, too.

Ted Fry: tedfry@hotmail.com