Process first 3 ingredients in a food processor until finely crushed. Firmly press mixture onto bottom of a lightly greased 10-inch springform pan.
Bake at 350° for 10 minutes. Cool completely in pan on a wire rack.
Let vanilla ice cream stand at room temperature 20 minutes or until slightly softened.
Process strawberries and 2 tablespoons powdered sugar in a food processor until pureed, stopping to scrape down sides; remove strawberry mixture, and set aside.
Process blueberries and 1 tablespoon powdered sugar in food processor until pureed, stopping to scrape down sides; set aside.
Mash bananas with a fork in a large bowl; stir in remaining 1 tablespoon powdered sugar. Set aside.
Place 1 quart of ice cream in a large bowl; cut into large (3-inch) pieces. Fold strawberry mixture into ice cream until blended. Place in freezer until slightly firm.
Divide remaining quart of ice cream in half, placing halves in separate bowls. Stir blueberry mixture into half and mashed banana mixture into remaining half. Place bowls in freezer.
Spread half of strawberry mixture evenly into prepared crust in springform pan. Place pan and remaining strawberry mixture in freezer. Freeze 30 minutes or until strawberry layer in pan is slightly firm. Spread banana mixture evenly over strawberry layer in pan; return pan to freezer, and freeze 30 minutes or until banana layer is slightly firm. Repeat procedure with blueberry mixture. Spread remaining strawberry mixture over blueberry layer in pan, and freeze 3 hours or until all layers are firm. Let pie stand at room temperature 15 minutes before serving. Garnish, if desired.
Note: For testing purposes only, we used Häagen-Dazs ice cream.