Mark Yonally's latest tap-dance narrative, Changes: A Science Fiction Tap Opera, is even more campy than last summer's "The Tell-Tale Tap: Stories of Edgar Allan Poe." Set entirely to songs by David Bowie, the evening-length Changes begins where "Space Oddity" leaves off: Major Tom gets lost, then crash-lands on a planet ruled by cruel dictator Altego (played by Yonally himself, "glammed the hell out," as he says). Eventually Major Tom frees the planet's citizens from slavery in what Yonally calls a "rousing space adventure" with a subtext: the sci-fi angle allows him to satirize egotistical leaders and state-sanctioned torture. The dancing itself is straightforwardly satisfying, underlining or playing off the music's rhythms while providing the story's details and emotion. And its thunderous reverberations, especially when all or most of the 11 cast members are performing, magnify the saga, giving it an operatic scope. Through 7/30: Fri-Sat 8 PM, Sun 3 PM, Athenaeum Theatre, Studio 3, 2936 N. Southport, 312-902-1500, $15-$25, discounts for groups of 15 or more.