"Sunday living/Seven days a week"--so goes one chorus on the debut of Austin's Brothers and Sisters, Texas' newest and brightest purveyors of easygoing '60s-style country-rock. In concert, the band more than lives up to their name, mixing the family-style harmonies of the Mamas and the Papas with the chiming guitars and classic songwriting of the Byrds--in other words, the perfect soundtrack for that sunbaked hippie stranded out where the surf meets the desert. San Francisco's The Court and Spark closes the show with its own cloudy and venomous mix of the same cosmic country Kool-Aid. Foul-mouthed Austinite (and Observer favorite) Pink Nasty opens. Mark your calendar, tie a ribbon around your finger, whatever--just don't forget this midweek treat.