You can bet that plenty of hardcore fans will be at each installment of Built to Spill's three-night run. The beloved Boise alt-rockers never play the same show twice, changing set lists and loosening up compositions to make room for Doug Martsch's famous guitar heroics: He chisels out tiny, shiny hooks and erupts into monumental solos. The band's most recent singles are an original reggae-rock jam and a cover of "Re-Arrange" by roots legends the Gladiators—proof that Built to Spill are still searching for new sounds to explore. (Showbox at the Market, 1426 First Ave, 628-3151. 8 pm, $18 adv/$20 DOS, 21+.)