Strange to see North Carolina’s Avett Brothers in casual-wear–understandable because of the lack of shade. Stranger still to see them strumming banjo and guitar in front of an audience of thousands, whereas back in the day last year or so the bluegrass-pop hybrid was drawing maybe a hundred folks–fewer still in the years before that. The Avett Brothers are a growing band and it’s easy to see why. For an acoustic four-piece whose bread and butter is songs about fraternal love other labors of the heart, they put put on one hell of a raccuous live show–all spasitic banjo and jittering upright base. To borrow a line from a classic ad campaign, you probably don’t know them now, but you will.