Arlo Guthrie, Saturday, February 17, at the Boulder Theater, has accomplished far more in his career than writing "Alice's Restaurant" nearly thirty years ago. He's also created a body of work strong enough to move him out of the enormous shadow cast by his father, folk legend Woody Guthrie. His easy charm and quirky hipster persona may be the characteristics that most listeners associate with him, but his original compositions are memorable, too; he stamps his takes on country, blues and folk with humor and pathos that could come from no one else. Equally fine are his interpretations of spirituals (his "Amazing Grace" is a vivid example of white-boy soul) and tunes by accomplished artists such as the late Steve Goodman. And as if that's not enough, Arlo will be joined for this date by his son Abe, a fledgling artist already staking out his own turf in the world of contemporary folk. It must run in the family.