Twenty years of O.A.R. has felt like "it just happened a minute ago" to frontman Marc Roberge.Until, that is, he looks at some pictures from the group's earliest days."Yeah, then it's clear it was 10, 15, 20 years ago," Roberge, who co-founded the group in 1996 with school friends from Maryland (who all later attended Ohio State University), says with a laugh by phone.