Varttina would be the ultimate stumper in a game of "Name That Tune," because the Finnish group really is one of the oddest-sounding ensembles around. Much of the music on Varttina's 10th and newest album, "Iki" (Northside Records), could pass for Irish folk -- but with exotic tempos and cadences and lyrics that sound out of this world, not just out of this hemisphere. So it figures that Varttina's next project will take the group to Middle Earth, providing the score for the stage version of J.R.R. Tolkien's "The Lord of the Rings." In the interim, Varttina plays Thursday at Duke University's Reynolds Auditorium.