The concept of the Ten Out of Tenn Christmas Tour is very simple. The troupe of singer-songwriters (who all live in Tennessee — get it?) hop in a bus, travel from town to town and put a festive, seasonal spin on their increasingly popular mobile musical revue. Although each performer has a slightly different take on the mellow, introspective AAA format, standout artists include Erin McCarley, whose piano-swept tune "Love, Save the Empty" swoons with Regina Spektor-like cinematic flair; funky soul-folkie Butterfly Boucher, who dueted with David Bowie on the Shrek 2 soundtrack; Elvis Perkins-esque crooner Andrew Belle and corn-fed rocker Trent Dabbs, who's opened for R.E.M.