Session Americana sit tightly around a small café table, ambient mics tuned to catch the whole sound of the voices and instruments. Asuitcase drum kit, an old electric bass, a bunch of acoustic instruments, a field organ — this format feels very theatri-cal and though the musicians face each other, the audience feels drawn into the circle by the warmth, joy and camaraderie that emanate outwards by theall star cast of characters seated around the table. What keeps you coming back show after show is the same thing that any audience member longs for — great songs performed by a great band. The six core members of the band have brought enviable careers worth of experience to the "table", featuring(current and former) members of Treat Her Right, Patty Griffin, Lori McKenna, The The, Dennis Brennan and Kris Delmhorst. The group has grown from a rag tag jam at a local pub into a regionalinstitution, playing gigs from church coffee houses to urban nightclubs, from regional festival tents to large halls. The band has sold out Harvard Square's legendary Club Passim, and has performed at special events including Boston's historical "First Night" ringing in the new year.