Buying instruments with cash netted from a bar fight, UB40 couldn’t have had a more humble start (especially since, once they got the instruments, the band still didn’t know how to play them). Nevertheless these working-class guys from the West Midlands of Britain became one of the most adventurous — and commercially successful — reggae bands of all time. Featuring original band members Ali Campbell, Astro and Mickey Virtue, the Grammy-nominated group brings their signature high-energy, funky sound to the Ravina Pavilion in Highland Park for the Ravina Festival. With a smooth-yet-rootsy blend of reggae and pop, UB40 has sold more than 70 million albums and charted dozens of global hits, including “Red Red Wine” and “Can’t Help Falling in Love.”  Tickets to their September 2nd performance are $30-35 on Goldstar.