In a medium mixing bowl, combine the graham cracker crumbs, melted butter, and granulated sugar. Mix together with a fork until thoroughly combined, then press the mixture firmly into the bottom and up the sides of a 9 inch pie plate. Bake at 350°F for 8-10 minutes. Cool completely.
In a large mixing bowl, combine the pudding mix, milk, and sour cream. Use a hand mixer on medium speed to mix until smooth and creamy. Fold in 2 sliced bananas. Spoon the filling into the crust and refrigerate for 10 minutes.
In a separate medium mixing bowl, beat the cream cheese with a hand mixer on medium speed until smooth. Add the Cool Whip and mix together until creamy. Spoon the topping evenly over the pie filling.
Cover with plastic wrap and chill for 3 hours. Remove from refrigerator and top with additional sliced bananas.