"Make 'em Dance: The Hackberry Ramblers' Story" profiles fiddler Luderin Darbone and accordionist Edwin Duhon, who have been playing their infectious blend of Cajun and country music since the 1930s. They've lived to tell about it, and to play on MTV, and they're doing both in this delightful profile, which follows the pair on the road, and back to Hackberry, La., where they founded their band.