In 1979–the year WLUP hosted Disco Demolition Night at Comiskey Park and I learned to polka in gym class–the boys of Brave Combo turned to polka, not punk, to thumb their noses at commercial music. Like any polka purveyors worth their pilsner, they’re brilliant musicians but modest enough to make sure that every flickering clarinet run and deft horn minisolo slavishly serves the danceable tunes. And like anybody who’s stuck with an endangered music for 25 years, they’re as stubborn as my gramma: in liner notes, in PR materials, and in interviews, they insist nonstop that the genre they love is hip and relevant, goddammit. In 2000 the band even spearheaded a boycott and letter-writing campaign that convinced Pepsi to pull a TV ad “implying that polka music is stupid.” Perhaps it can’t match rock ‘n’ roll in the bad-boy posturing department, but if anything polka is better suited to lusty crossbreeding with other ass-shakin’ music: Brave Combo has pulled off a swing cover of “Hava Nagila,” a whole album of Latin-infused polka, a “rock” version of the hokey pokey that sounds like acoustic rap, and a beautiful, tangofied “Louie Louie” that could pass for an entirely different song. I’ve only heard a fraction of their output–they’ve released more than two dozen albums–but “Willkommen Oktoberfest,” a giddy, soulful polka from the new Let’s Kiss (on the band’s own Dentone label), seems to sum up Brave Combo’s mission: “Open up your heart and try to feel the joy and the power of polka music / There’s nothing like it anywhere you go!” This is a holiday-themed show. Sat 12/4, 10 PM, FitzGerald’s, 6615 Roosevelt, Berwyn, 708-788-2118 or 312-559-1212, $15.