Improv usually works best when it puts less emphasis on concept and more on execution; an ambitious concept can be so distracting that the actors forget to be funny. That's certainly the case with the Un-Scripted Theater Company's fourth annual production of Let It Snow!, billed as "an improvised holiday musical" and performed by a peppy rotating cast. The show begins with director Mandy Khoshnevisan asking random audience members to describe their hometowns. Then the audience votes on which place of origin sounds most interesting (or most horrifying), and the troupe performs a two-hour holiday musical set in that town. It's a cute idea, but it would be cuter as a 30-minute lark — two hours of improvised singing is asking an awful lot of both actors and audience. At a recent preview (set in the Central Valley burg of Paradise), the actors broke into a tentative production number every 10 minutes or so, but that sort of trick is only funny if the numbers are funny, and these weren't very funny at all. Maybe it works better with a different cast warbling about a different hometown — but Let It Snow! feels like a concept that just doesn't sing.
