WILKESBORO, N.C.-Characterizing the music of the Washington, D.C.-based band Scythian is no easy task. The quintet led by brothers Danylo and Alexander Fedoryka feature banjo, fiddle, guitar, and mandolin. That sounds like bluegrass. But the group also has a rollicking drummer, plus an accordion and a viola, with touches of Celtic and Gypsy (from the brothers' Ukrainian ancestry), not to mention a frenetic stage presence with large doses of audience interaction. Think of a house party where bluegrass meets klezmer, with all your crazy cousins thrown in for good measure.