Brave Combo does a polka version of James Brown’s “Sex Machine” and a cha-cha adaptation of the Stones’ “Satisfaction,” but it’s by no means a mere novelty act. Back in the area to promote Polka for a Gloomy World, the 16-year-old Dallas ensemble cleverly fuses a broad spectrum of Southeastern and Latin American genres and a rambunctious rock ‘n’ roll sensibility. At 8:30 p.m. at Tornado Alley, 11310 Elkin St., Wheaton. $7. (301) 929-0795. (SK)