The design-minded residents of Eagle Rock spent many years crafting zoning laws to limit the number of auto repair shops along Colorado Boulevard. Many of those muffler and tune up shops are still there, however, defying a wave of gentrification that has filled the boulevard with vegan restaurants, yoga studios and new bars. Instead of ignoring some of these homely, oil-stained spots, the organizers of tonight’s Eagle Rock Music Festival have over the years teamed up with the repair shop owners, who have opened their service bays and storage yards to musical acts and fans. At tonight’s musical festival, the Eagle Rock High School Latin Jazz Band, for example, will play at Rantz Automotive. The former American Tire Depot, meanwhile, will host The Pulsars and The Pitty Party.