There’s no good way to explain the context in which the phrase “haunted rape trail” was funny. But it was. It really, really was, the last time the Extemporaneous Theatre Company did a Whose Line Is It Anyway?-style comedy showcase. See, the way that it works is that bang-up ensemble of local stand-up comedians and actors \’97 including Doug O’Neil Jr., Chris Davis, Debbie Smith and Callie Mauldin \’97 takes the stage armed only with a premise, and then the audience provides details for them to riff on. ETC has such three performances this weekend at Birmingham Festival Theatre \’97 check out “Project Codename: Vulcan’s Underpants” at 8 p.m. on Friday and Saturday, Feb. 20-21 (or a family-friendly matinee at 2 p.m. on Saturday, Feb. 21). Advance tickets for Saturday are available at http://extemporaneoustheatre.com/. Tickets for Friday night, billed as “The Lincoln’s Birthday Show” are available at the door. All walk-up tickets are cash-only. Birmingham Festival Theatre is located at 1901 1/2 11th Ave. South, around the corner from The Golden Temple.