Preheat the oven to 350 degrees. Spray an 11 x 7 baking pan with cooking spray.
In a large bowl combine the cake mix, oil, egg, and milk. Mix well until combined.
Stir in the sprinkles and the chocolate chips.
Pour the mixture into the prepared pan and sprinkled a few extra sprinkles on top.
Bake for 25-30 minutes or until the edges are beginning to brown.
Remove from oven and cool completely on a wire rack. Cut into 15 squares and enjoy!