After Marcia talks Carol into performing in the school's Family Frolics talent show, Greg gets Mike in on it, too. And what they come up with brings down the house. The man with the accordion is Frank DeVol, composer of the show's classic theme song. Sam: Allan Melvin. Mrs. Tuttle: Barbara Morrison. Woman: Brandy Carlson. Marcia: Maureen McCormick. Carol: Florence Henderson.