After their four-Oscar triumph with last year's “No Country for Old Men, Joel and Ethan Coen are back to their old tricks that worked so well in “Fargo” - a sort of noirish-screwball comedy in which terrible things happen to really stupid people.

One of the best things about “Fargo” is also one of the best things about their new movie, “Burn After Reading,” and that's the performance of Frances McDormand. She's married to one of the Coens – I can never remember which – and has appeared in six of their films, winning an Oscar for her work in “Fargo.”

She probably won't get nominated for her work in “Burn After Reading,” but she's still fun to watch for about the first two-thirds of the movie. In fact the fun runs out of just about everybody's performance around then, and the cast just labors on going nowhere, like running on a treadmill.

Treadmills are almost a leitmotif, because McDormand's character, Linda Litzke works at a Hardbodies gym in DC. Here we come to another casting high point: Brad Pitt finally in a role that suits him to perfection, a gym trainer named Chad who has really bad blond highlights and nothing between the ears but marshmallow fluff.

Chad is Linda's buddy, who advises her on “losers” as she cruises an internet dating service, and enables her fantasies about major cosmetic surgery, which the gym's health plan, naturally enough, won't pay for.

Meanwhile, over at the CIA (of course), analyst Osbourne Cox (played with foul-mouthed glee by John Malkovich) has been fired because of a drinking problem. Of course Cox claims that his sacking is political, and we almost believe him until we see him passed out face-down in an arm chair, a position that's pretty hard to achieve.

Tilda Swinton plays Cox's wife as the White Witch of Narnia, and wants to divorce him for the worst of all possible reasons: she's having it off with George Clooney, playing a repulsive Treasury agent who's an insult to jerks everywhere. (When they have sex they both wear their gold chains in bed, to give you an idea.)

Mrs. Cox's smarmy divorce lawyer urges her to make a copy of all the family finances, and here's where the going gets rough, because through a twist I completely missed, the CD she puts the info on ends up in the locker room at the gym, where Chad predictably interprets it as Top Secret data.

He somehow gets Osbourne Cox's name off the disk, and suggests to Linda that they return it for a large “reward,” enabling her to get her liposuction and him a decent haircut. Of course Ozzie profanely refuses, so they decide to sell it to the Russians, which, plus the fact that Linda meets George Clooney on her dating service, is all you need to know.

The trouble with all the clever-clever set-up is that the blow-off just runs down like the universe on entropy, and the characters flail madly about, getting stupider and more violent by the frame, with the top-flight cast looking increasingly uncomfortable, as you would too if you were trapped in a bad joke.

J. K. Simmons (editor Jonah Jameson in the Spiderman movies) has two great scenes as the CIA head who has trouble following simple declarative sentences. And in this whole cast of misfits and morons there is one genuinely sweet and compassionate character, and John Malkovich chops him to pieces with a hatchet; it's a funny old world.