1Heat oven to 350°F. Make and bake cake as directed on box for 13x9-inch pan. Cool completely, about 1 hour.
2In large bowl, crumble cake. Add frosting; mix well. Roll into 1-inch balls; place on wax paper-lined cookie sheet. Freeze about 45 minutes or until firm. Refrigerate to keep chilled.
3In 1-quart microwavable bowl, microwave 8 oz of the candy coating uncovered on High 1 minute 30 seconds; stir. Continue microwaving and stirring in 15-second increments until melted and smooth.
4Remove one-third of the balls at a time from refrigerator. Using 2 forks, dip and roll 1 ball at a time in coating. Place on wax paper-lined cookie sheet; immediately decorate with sprinkles. Refrigerate cake balls about 10 minutes or until coating is set. Melt remaining candy coating in 6-oz batches; dip remaining balls. (Reheat coating in microwave if it is too thick to coat.) Serve at room temperature. Store in airtight container.