One weekend a month, Second City alumni David Pasquesi and TJ Jagodowski headline at New York’s Barrow Street Theatre, where director Alex Karpovsky (Woodpecker) captured a performance for this behind-the-scenes documentary. Unlike players at their alma mater, who develop comic ideas in rehearsal and assemble skits into long-running revues, the quicksilver “TJ & Dave” improvise something new each night, without conferring beforehand on how to fill their roughly 55 minutes on stage. As seen here, their risky, cerebral approach can result in three-act comedy as dizzying as a high-wire act, but the movie’s first 18 minutes, in which the actors discuss their process, isn’t as revealing as their post-performance recap. 80 min.