Prepare cake mix as directed. Bake in well-greased and floured 9" x 13" pan @ 350-degree oven for 30-35 minutes. Cool in pan for 15 minutes. Poke with fork@ ½ "intervals. Dissolve Jell-O in boiling water. Add cold water and stir. Pour over cake in pan. Chill 3-4 hours. Top with thawed Cool Whip.