Heat oven to 350°F (325°F for dark or nonstick pans).

Place paper baking cup in each of 24 regular-size muffin cups.

In large bowl, beat cake mix, water, oil and eggs with electric mixer on medium speed 2 minutes, scraping bowl occasionally.

Divide batter evenly among muffin cups, filling each two-thirds full.

Bake 14 to 19 minutes or until toothpick inserted in center comes out clean.

Cool 10 minutes; remove from pans to cooling racks.

Cool completely, about 30 minutes.

Place candy sprinkles in shallow bowl.

Fill large resealable food-storage plastic bag with 1¼ cups frosting; cut off tiny bottom corner.

Pipe frosting in a circle one time around outside edge of cupcake.

Dip edge of frosting into sprinkles.

Reserve remaining frosting in bag for pom-poms.

Among 3 small bowls, evenly divide remaining frosting (about 1⅓ cups each).

Tint frosting in bowls with food colors: 1 red, 1 green and 1 blue.

Place frosting in 3 small resealable food-storage plastic bags; cut off tiny bottom corner of each bag.

Pipe red frosting, starting on inside edge of white frosting and spiraling up toward center to form a hat; continue red piping on 7 additional cupcakes.

Repeat piping with green and blue frosting with remaining 16 cupcakes (8 cupcakes each).

Pipe a small dab of reserved untinted frosting on top of each hat for pom-pom.