collins, tom and dick, the smothers brothers, the kingston trio, the highwaymen, the brothers four, glenn yarbroughroger mcguinn, barry mcguire, randy sparks and the minstrels unite for history in a special celebration of american folk music... next on pbs. ♪ ♪ rows and flows of angel hair ♪ ♪ and ice cream castles in the air ♪ ♪ and feather canyons everywhere ♪