Heat oven to 325 degrees F. Generously grease the inside of a 12-cup fluted bundt cake pan.
Make cake mix according to packaged directions. Tip: To cut down on fat, substitute the oil with applesauce.
Pour 1 cup batter each into two separate bowls. Stir in desired amount of red food coloring in one bowl and blue food coloring in another. Mix well.
Pour the red batter into the bottom of the pan and spread it out evenly with the back end of a spoon.
Gently pour the white batter over the top of the red batter covering completely. If needed, use the back end of a clean spoon to spread out the batter.
Carefully pour the blue batter over the center of the white batter. The blue batter does not need to completely cover the white batter. In fact, it looks best if you pour the blue in the center of the white and not have it spread out.
Bake according to cake package directions or until a toothpick inserted in the center of the cake comes out clean.
Remove from oven and allow to cool 5 mins in pan before inverting cake onto baking rack to cool completely.
Meanwhile, evenly divide frosting into 3 separate microwavable bowls. Microwave one bowl of frosting on high for a few seconds until frosting is of a drizzling consistency. Stir in a few drops of blue food coloring until smooth. Using a spoon, drizzle frosting back and forth over cake creating a striped pattern. Repeat with second bowl using white frosting, and third bowl with red food coloring.
Light sprinkle the sprinkles for garnishment.
Let stand at room temperature until frosting is set. Transfer to a clean cake plate before serving.