Some musicals work only on a huge, expensive set. But Joseph Dougherty, Stephen Flaherty, and Lynn Ahrens’s 1992 show, based on the 1982 movie, creates theater the old-fashioned way: with a good story and score and interesting characters. In this tale of a fledgling TV writer, many of them are fictionalized versions of the talented crazies who helped create Sid Caesar’s seminal 50s comedy Your Show of Shows. With casting as strong as it is in David Zak’s energetic production, it doesn’t matter if your set looks like it cost $1.98. Michael S. Mahler and Megan Long are charming as the would-be couple at the center of the story. But Kevin Mayes, in a killing imitation of Errol Flynn, steals the show. –Jack Helbig a Through 4/8: Thu-Sat 7:30 PM, Sun 3:30 PM, Bailiwick Repertory, Bailiwick Arts Center, 1229 W. Belmont, 773-883-1090, $25-$30.