1 white cake mix
1 - 3oz. pkg. fruit gelatin (jello)

Prepare cake according to directions on box and bake.  Cool for 20 minutes. 

Mix fruit gelatin with 3/4 cup boiling water.  Stir to dissolve.  Add 1/2 cup cold water and mix again.

Poke holes all over top of cake.  Pour warm jello mixture over top of cake.  Place in refrigerator.

Make topping:
1 envelope whipped topping mix
1 pkg. vanilla instant pudding
1 1/2 cup cold milk
1 tsp. vanilla

Beat together about 5 minutes or until stiff and peaks form.  Spread over top of cake and chill in fridge until ready to serve.  Store in fridge.

For a fun variation, you can use half of one color/flavor of jello on one side of the cake, and another flavor on the other half.

You can also substitute real whipped cream and pudding mix for the topping, or try using cool whip and pudding.