Preheat oven to 400 degrees. Mix margarine and crumbly mix (from date bar mix) with a fork. Spread in 9x13 inch baking dish. Bake for 10 minutes (do not overbake); remove from oven and stir to break in pieces. Reserving 1/2 cup for topping. Press remaining mixture in bottom and sides of a 9 inch pie pan. Cool.
In a mixing bowl, mix together date filling mix and hot water. Cool. Spoon ice cream into pie shell and spread date filling on ice cream. Sprinkle remaining crumbly mixture on top. Serve immediately or freeze for a later use.