Rooftop Vigilantes' live shows have a tendency to go awry — in a good way. Each show's punk-rock spirit occasionally causes broken strings, faulty cables and burned-out amps, but the band plows through technical difficulties in a way that makes Rooftop Vigilantes one of the best live acts around. A recent performance at the Replay Lounge found singer and bassist Oscar Allen running across the street to borrow a bass guitar from a metal band while singer and guitarist Zach Campbell and keyboardist Hannah Hyde serenaded the audience with an on-the-fly rendition of Del Shannon's "Runaway." When Allen returned, the band picked up right where it had left off, kicking out raucous, punky power pop in the spirit of the Replacements and Guided by Voices. The Yuppies and the Prairies are on Friday's bill as well — Nebraska bands that play hyper-distorted punk which will have your eardrums begging for mercy.