After the portentous No Country for Old Men, Joel and Ethan Coen return to their trademark brand of cruel, misanthropic farce, and for dark laughs and hurtling narrative momentum this 2008 spy caper is their best work since Fargo. The plot is a similar vortex of greed, misunderstanding, and plain stupidity, as two dim-witted health club employees (Frances McDormand and Brad Pitt) decide they’ve stumbled onto the tell-all memoir of a disgruntled CIA analyst (John Malkovich) and set out to blackmail him, or the U.S. government, or somebody. The Coens are masters of casting, often called the director’s key task, and here they’ve assembled an impeccable ensemble of icy dramatic talents (Malkovich, Tilda Swinton), box-office hunks displaying their comic chops (Pitt, George Clooney), and indelible character actors, some known by name (Richard Jenkins, J.K. Simmons) and some who ought to be (Kevin Sussman, Michael Countryman, Olek Krupa).