Place layers top sides in 2 (9 inch round cake pans. Pierce cake with large fork at 1/2 inch increments. Stir 1 cup boiling water into each flavor of the gelatin in separate bowls 2 minutes or until dissolved. Carefully pour red gelatin over 1 cake layer and lime gelatin over the second cake layer. Refrigerate 3 hours. Dip 1 pan in warm water for 10 seconds; unmold onto serving plate. Spread with 1 cup of whipped topping. Unmold second layer, carefully place on first layer. Frost with remaining whipped topping. Garnish as desired. Refrigerate for 1 hour before serving.