Prepare the brownie batter according to the package directions. Fold in the rainbow sprinkles and white chocolate chips.
Pour the batter into a prepared baking dish and bake according to the package instructions. Let the brownies cool completely.
Cut the brownies into bite-sized pieces. Add a layer of brownie chunks into serving glasses or bowls. Spoon warm hot fudge over the brownies, then top with a scoop of marbled chocolate and vanilla ice cream.
Finish with a soccer ball sugar cookie and extra rainbow sprinkles on top. Serve immediately while the brownies are still a little fudgy and the ice cream is perfectly melty.