Check out the influences of just about any bass player going these days, and you'll find a sworn allegiance to Primus's Les Claypool, who for seven albums and countless side projects and guest appearances has been warping the fat-stringed minds of rock bass men everywhere. Otherwise jokey in his lyrics, stage presence and overall imagery, Claypool puts on a veritable bass-guitar clinic each time he picks up his instrument in front of an audience. You'd be hard-pressed to find a mainstream band with more complicated time signatures and snakier rhythms, and Primus's stamp is felt on newer bands from Minus the Bear to System of a Down. Fresh on the heels of its dates this past summer at Red Rocks with the Flaming Lips, Primus returns to Denver in support of the just-released Green Naugahyde, its first proper studio work since 1999's Antipop.