Prepare and bake cake mix according to package directions for a 9x13 inch pan. Poke holes in cake while still hot with a fork. Make gelatin with 1 cup of boiling water, then stir in cold water. Slowly pour liquid gelatin over hot cake. Cool cake completely in the freezer before frosting.
To make the frosting: Using an electric mixer, beat together the instant pudding, whipped topping and milk until thickened. Pour over completely cooled cake. Keep cake in freezer until ready to serve.