As an alumnus of the late-'90s, early Warped Tour-type scene, Authority Zero is one of the few acts of its ilk not only surviving but thriving on the underground circuit. The group has long specialized in fast, no-frills skate punk blended with reggae and a little ska. It's nowhere near as poppy as, say, a 311, but the band's alternately chilled-out and amped-up jams similarly appeal to a broad cross section of live-music fans. Onstage, in fact, is where the group is particularly beloved, something reflected by the fact that its newest release, Less Rhythm, More Booze, is a live CD/DVD set. For this show at Respectable Street, it even comes partnered with fellow ska-punk lifers and Southern California group Voodoo Glow Skulls.