There's nothing radical about O.A.R. , whose music will never incite anarchy or massive social change, despite what its full name (Of a Revolution) implies. Rather, the Ohio quintet's output fits comfortably alongside radio-friendly jam outfits such as Guster and the Dave Matthews Band. But O.A.R. is a poster child for guerrilla-style DIY success, having begun as a workaday frat band and slowly taken over America by word of mouth, Internet marketing and relentless touring. The band's independently released 2002 double-CD live album Any Time Now sold in excess of 100,000 copies, a number impressive enough to score the group a major-label deal. Fortunately for fans, O.A.R.'s Lava debut, In Between Now and Then, retains the group's trademark ingredients: breezy rhythms, galloping acoustic guitars and a rock-based palate that leaves room for reggae and ska flourishes. In a live setting, these influences meld together seamlessly, and the twentysomething road vets have perfected the art of in-concert merrymaking.