Grease a 9 x 13 pan. Make the cake according to the box. Let cool. Make the jello according to the box, once boiled pour in a measuring cup. Take a cooking spoon and use the handle to poke holes in the cake. Pour the jello into and all over the cake until it's all soaked in.Add the cool-whip to the cake and spread evenly. Then chill the cake for 4 hours until the jello is set. Then serve.