E-Mail This Article to a Friend Start the revolution O.A.R. come to the Orpheum BY SEAN RICHARDSON

Last year, suburban DC roots-pop heroes O.A.R. (Of a Revolution) released their first major-label album, In Between Now and Then (Atlantic), and hit the road with N*E*R*D and the Roots on the Sprite Liquid Mix Tour. They moved even farther into the mainstream when the disc’s first single, "Hey Girl," became a modest hit on adult-alternative radio. But touring remains their calling card, and this week they’re playing two shows with sacred-steel stars Robert Randolph & the Family Band at the Orpheum in the middle of a six-week US headlining jaunt.

Like any other grass-roots success story, O.A.R. have been doing their thing below the pop-cultural radar for years. Debuting in the late 1990s with two self-released, no-budget discs, they became one of the biggest word-of-mouth phenomena of the Napster era while attending Ohio State University as a group. The 10-minute reggae/hillbilly blowout "That Was a Crazy Game of Poker" was an instant jam-band classic, and in 2002 they hit the Billboard 200 albums chart for the first time with the double-live collection Any Time Now on their own Everfine label.

"Hey Girl" is one for the ladies, an upbeat puppy love sing-along that frontman Marc Roberge wrote when he was a teenager. It’s been in the O.A.R. repertoire since day one, and this is the fourth time they’ve put it on one of their albums. "At the time Marc felt like, ‘I’m 16 years old — what is it that I really know?’ " explains drummer Chris Culos when I get him on the phone from Philadelphia on the first day of the tour. "It’s a simple song about a girl and a date, but over the years it’s become a concert staple because we play it differently every night. On this album, we put all our favorite parts from all the different versions into three minutes. To somebody new to the band, a 25 year-old guy singing, ‘Hey girl, come with me’ — it makes a little more sense when you hear the whole story."

In Between Now and Then is based more on hooks than on virtuosity: the album has a loose feel, but O.A.R. don’t jam as much as their most obvious influence, Dave Matthews Band. Upcoming single "Right on Time" kicks off with a biting guitar line that could set the stage for a DMB-style modern-rock crossover. "When we recorded that song, we thought, ‘This is our first attempt at a rock song,’ " Culos laughs. "But I think it has a lot of the same elements that we’ve always had, even though there may be a little bit of distortion on the guitar." He praises star producer John Alagia (John Mayer, Jason Mraz), who’s been working with the band since 2001’s Risen. "We’ve formed such a cool friendship out of what started off as hiring a producer to do the job. It’s fun to work with him, because we know what he wants from us, and it’s the other way around, too."

Internet file sharing played a crucial role in the rise of O.A.R., whose members were living in different cities and rarely performing together when their music first hit the Web. "When Napster started taking off, it was a way for our music to spread without us having to play across the country, because we couldn’t at the time," Culos points out. "It was the greatest thing to ever happen to us, because we’d go to a place for the first time and there would be people there singing back to us. It was scary — it’s like, ‘We’ve never been to St. Louis, and these people know the words.’ "

O.A.R. perform tonight and tomorrow, February 12 and 13, at the Orpheum Theatre, 1 Hamilton Place in Boston; call (617) 679-0810.