This year, Clowes Hall introduces Clowes Off Center, an alternative series of shows that promise not-quite-mainstream entertainment. This one seems perfect for that rubric. It features improvised songs and sketches (for mature audiences) using puppet mastery from The Jim Henson Company. But this definitely isn’t “Muppet Show” humor. If you grooved on “Avenue Q,” this could be the variety show you’ve been, without realizing it, waiting for. Details here.