Prepare and bake cake according to box directions in a 9 X 13-inch baking pan
When the cake is cooled, combine 1/2 cup boiling water with blue jello in a bowl. Stir until dissolved. In another bowl, combine 1/2 cup boiling water with red jello. Stir until dissolved.
Use a wooden spoon and poke several holes in the cake. Carefully spoon jello mixtures into the holes, trying to only pour one color into each hole. Be sure to spread the colors throughout to create a fun color pattern.
Place cake in the refrigerator for 30 minutes to allow jello to soak in.
Remove from the refrigerator and frost with whipped topping
Sprinkles the top of the cake with Red White and Blue Sprinkles