The closed sign had been flipped over for a while last Sunday evening at the Tap Room when 12 actors at a back table rolled through the first reading of a West Marin Christmas tradition. One had twisted his ankle en route to the rehearsal and sat icing it with his leg propped up on a chair—but the injury was no deterrent. “This is why I love radio plays. “Twisted ankle? Not a problem!” actor Matt Gallagher said. The thespians were practicing for their upcoming one-off performance of “It’s a Wonderful Life,” based on the holiday heart-warmer that was originally a short story called “The Greatest Gift” but is probably best remembered for its 1946 film adaption. The story follows American dad George Bailey, a diligent loan man, on an insightful Christmas Eve when he’s offered a glimpse into how his hometown of Bedford Falls would have been without him. The troupe has performed the Christmas classic as a radio play based on contemporary playwright Joe Landry’s adaptation each year since 2015. “Somehow, with the stripped-down-to-the-bare-bones version, there’s something very different about it and it seems so evidently simple. It’s a very sweet play to do,” Sharron Drake, the show’s producer, said. The lively performance is guided by an applause sign that brings the audience into the show and, since it’s a radio production, the sounds tend to be more important than the visuals. (Giovanni DiMorente provides music.) This year, for the first time, the show will raise funds for KWMR (Ms. Drake joined the radio station’s board last month), though it will not be broadcast over the air due to copyright restrictions. That won’t hinder the show’s producer and cast from reimaging the Dance Palace stage as a radio station on a festive Christmas Eve in the 1940s. New additions to the production this year include the casting of five children in roles originally written for adults and the inclusion of original jingles to credit the show’s 11 local sponsors. Last week was the troupe’s first stab at rehearsing these hilarious promotions, which include an ode to the menu at The Side Street Kitchen sung to the melody in “Rudolf the Red-Nosed Reindeer.” (The Light is a sponsor; our plug manages to blend zucchinis, the Sheriff’s Calls and Art Rogers into a single jingle.) In her third production of the classic, Ms. Drake’s arsenal of sound effects has also grown, and she admitted to splurging on eBay for a 1940s-era telephone to generate dialing sounds. “Every year we can improve,” she said. “Next year it will be the cash register sound.” “It’s a Wonderful Life: A Live Radio Play” shows at 7:00 p.m. on Sunday, Dec. 17 at the Dance Palace Community Center. $15 tickets are available at kwmr.org. Come in 1940s finery, and enjoy holiday sweets and Mike and Alex’s photo booth.