Preheat your oven to 350°F (175°C) and line a cupcake pan with paper liners.
In a large mixing bowl, combine the cake mix, water, vegetable oil, and eggs. Beat on medium speed for about 2 minutes until well blended.
Divide the batter evenly among the cupcake liners, filling each about two-thirds full.
Bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cupcakes to cool in the pan for 5 minutes, then transfer them to a wire rack to cool completely.
Once cooled, frost each cupcake with whipped topping.
Decorate with diced strawberries, blueberries, and a sprinkle of red and blue sprinkles.
Drizzle with a little vanilla extract for added flavor.