Though not related by blood, the Punch Brothers have an undeniable chemistry, melding their stunning string work and buttery-smooth voices into a form of modern bluegrass rooted in everything but tradition. Founded by Nickel Creek member Chris Thile in 2006, the quintet spin whiskey-soaked jams out of mandolin, violin, banjo, guitar, and bass. But their melodies never sit still, as they work their instruments with the intensity of a heavy-metal band on early laments like "Punch Bowl" and effortlessly harmonize through sharp tempo shifts—sounding like The Beach Boys gone prog—on ambitious suite "Familiarity."