Cult filmmakers in need of a cult, Mark and Michael Polish traffic in a brand of American weirdness uniquely their own, one in which every seedy hotel room and dilapidated trailer conceals a notable thrift-store find, a colorful character, and a story. In their debut, Twin Falls Idaho, the Polish brothers played conjoined twins unable to imagine life without one another. In the new Jackpot, they present another relationship of low-functioning codependence, this time between a singer (Jon Gries) hoping to climb to stardom by winning karaoke contests, and the manager (old-school SNL vet Garrett Morris) with the plan to get him there, even if they have to sleep in a car while they make the circuit. Framed, chronologically and thematically, by Gries' favorite number, George Jones' "The Grand Tour," the film flashes back and forth to portray Gries' hapless quest for stardom and the dissolution of his marriage to Daryl Hannah. Though technically effective, the leaps in time feel (as do many of the film's touches) like mere ornamentation. After a while, the oddities Gries and Morris encounter along the wayan aggressive Santa, a gap-toothed nymphet, and so ontake on the freak-show quality that Twin Falls so carefully avoided. But the central relationship carries a real poignancy, and Gries and Morris play it for all it's worth, with Gries' fatalistic stoicism complemented by his companion's unwavering enthusiasm. The latter usually takes form in Morris' twisted-logic managerial schemes, as when he counsels Gries to maintain an air of sexual ambiguity in order to maximize his audience, or charts the perfect song to match a particular crowd based on sex, date of birth, and general disposition. (It turns out to be Billy Idol's "Eyes Without A Face.") Co-written by the Polishes, with Michael handling the directing, Jackpot has a strong visual style, an even stronger grasp on its underworld-America milieu, and all the forward momentum of an abandoned Honda. It's far more memorable in retrospect than involving at the time; it brims with great performances and good ideas, but desperately needs discipline. Once they find that discipline, the Polish brothers may make a great film, but for now, they seem happy inhabiting the strange territory they've already staked out for themselves.