1 package white or yellow cake mix (for two layers)
4 eggs (for the cake mix)
1/3 cup oil (for the cake mix)
1 cup water (for the cake mix)
1 small package flavored gelatin, any flavor
1 cup water (for gelatin)
1 (12 oz.) container Cool Whip
Preheat oven to 350 degrees. Prepare cake, according to package directions, using eggs, oil and water. Bake cake in a 13x9-inch pan for 40 to 45 minutes. Let cake cool in pan for at least 15 minutes. Poke holes across the entire surface of cake with a fork. Dissolve the gelatin in 1 cup of boiling water. Pour the warm gelatin slowly over the surface of the cake (gelatin will soak into the cake). Place cake in the refrigerator and chill for about 4 hours. Spread whipped topping on top of cake before serving. Refrigerate leftover cake.
I found this recipe here.