Wandering down the quiet Greenwich Village street you’ll discover a humble handwritten sign advertising “Bluegrass Tonight” outside the leaf enshrined door of the Derech Amuno Synagogue at 53 Charles Street, on the corner of West 4th. Pull open the heavy wooden door and take a few steps down to the library/basement of the temple and you’ll find about twenty folding chairs are set up in rows of three and four. It’s quite an intimate setting to see a musical innovator of Andy Statman’s stature. When not on tour or in the recording studio you can find the mandolinist/clarinet virtuoso blending strains of bluegrass, free jazz and klezmer every Monday and Thursday night at the shule. For six and a half years now the low-key biweekly gig has allowed him to experiment with fresh ideas, while drawing from a batch of the city’s best improvisers, which has included such guest stars as David Grisman, Mike Marshall and Bela Fleck.