One of the most amusing trends in the last few years has been the merging of Southern rock and so-called stoner rock. As if we needed the unholy union of Sleep and Molly Hatchet. And yet someone was bound to make it work without sounding like a pack of rednecks who turned from crank to weed and mellowed out, man. Trading in ominous heaviness for punk's buzz-saw melodicism couched in metallic sound structures, Workhorse has managed to jump out of the rut of many of its peers. Instead of the dour stoicism of metal guys who mimic the faces favored by the gods of thunder, this band smiles on stage. Oh, sure, singer/guitarist Randy Olinger sounds like he gargles with a low molar solution of sulphuric acid in the morning, and lead guitarist Jay Ditchen bears an uncanny resemblance to David Cross, right down to the goofy grin. But they both play their cutting, subtly innovative hard rock as though they're having fun doing it. Maybe Workhorse (due at the Larimer Lounge on Saturday, July 7) is a bit of a misnomer, because these guys sure look like they're having a blast.