Bake cake in a 13" x 9" baking pan , as directed on box.
Poke holes over cooled cake using a fork or a skewer.
In a small bowl, mix gelatin with boiling water.
Stir until sugar is dissolved.
Pour gelatin over cake slowly, allowing it to fill the holes in the cake.
Frost with Cool Whip and add your desired topping.
Refrigerate for 4 hours, or overnight.