That’s the Way They Became the Grady Bunch by Antonia Mody This Cooperstown family has experienced the magic of The Glimmerglass Festival as audience members for decades. Now, they take the Glimmerglass stage together this summer. The Gradys, or the Grady Bunch as they are lovingly called, are all singing and dancing in Glimmerglass Festival productions this summer. The Sound of Music, playing now, features parents Kara and Matt, as well as Gavin, 12, who stars as Friedrich von Trapp.…