One would think, here and now, that disco has faded to a goofy relic of the past. For those born after the 1970s, disco exists only through YouTube videos of Soul Train and excerpted scenes from Saturday Night Fever and Thank God It’s Friday. Yet disco lives on, its flame carried in the heart of one local man, a Swiss immigrant past retirement age who frequents Cal Skate in Rohnert Park. If you’ve been roller skating there lately, you’ve seen him, often still decked out in beige bell bottoms and a matching polo. He weaves through the children stumbling around the rink with impressive grace, skating backwards and lifting legs, always faithful to the disco groove. Let his carefree demeanor and timeless shoulder-shrugging inspire dancers at Boogie Nights Dirty Disco, a ’70s-themed dance party organized with help from Sebastopol’s Funk and Flash. Dig the groove on Thursday, July 5, at the Hopmonk Tavern. 230 Petaluma Ave., Sebastopol. 10pm. $5. 707.829.7300.