To make the crust: preheat oven to 300ºF. Grease 9-inch pie plate. In medium bowl, combine graham cracker crumbs and sugar. Add butter; mix thoroughly. Press mixture onto bottom and sides of pie plate.
Bake 10 minute Cool completely.
To make the filling: in medium bowl, combine milk and pudding, stirring until thickened. Stir in sour cream just until blended. Pour into crust. Refrigerate 1 1/2 hours until set.