Joseph Gordon-Levitt and Bruce Willis in LooperLOOPER

Rian Johnson's Looper, a time-travel thriller set primarily in the year 2044, casts Joseph Gordon-Levitt as a contract killer whose life is upended with the arrival of his latest target: his older self, who has been transported from the year 2074 and is played by Bruce Willis. This means that, with Gordon-Levitt delivering rather uncanny likenesses of his co-star's traditional scowls and smirks - and with the younger actor's countenance bizarrely altered to resemble the elder actor's familiar face - Willis essentially plays both leading roles ... which isn't the most enticing of setups if, like me, you generally find one Bruce Willis more than enough.

Christopher Moynihan, Harry Shearer, Catherine O'Hara, and Parker Posey in For Your ConsiderationFOR YOUR CONSIDERATION

I love Christopher Guest's improvisational comedies with a passion bordering on mania, and he and co-scenarist Eugene Levy have been wonderfully consistent about treating fans to a new one every three years; 1997's Waiting for Guffman led to 2000's Best in Show and 2003's peerless A Mighty Wind. Now we have For Your Consideration, a skewering of the annual Oscar-derby madness, and I couldn't have been more excited about seeing it. So why, despite its many, many great moments, does reflecting on the director's latest leave me feeling disappointed, and a little depressed?

Eugene Levy and Catherine O'Hara in Best in ShowBEST IN SHOW

The genius of Christopher Guest lies in his belief that nothing is funnier than mediocrity. (He's the antithesis of Peter Shaffer's Salieri in Amadeus, who saw it as a tragic failure.) In his two finest cinematic efforts, This Is Spinal Tap and Waiting for Guffman, the performers examined in the "mockumentary" format - Tap's hard rockers and Guffman's thespians - were delightful because of their clueless self-satisfaction; they truly thought they were creating Art, or at least really kick-ass entertainment. And the joke blossomed every time we watched them perform their shows before audiences, because it turned out that these well-meaning hacks, while by no means terrific, weren't all that bad. They might have been lacking in talent, but their enthusiasm was infectious, and it made sense that their shows were hits. (God knows I've seen worse community-theatre productions than Guffman's Red, White, & Blaine.) Guest, who co-wrote both films and served as director for Guffman, was thereby able to poke fun at his characters and have you genuinely rooting for them at the same time.