If you do weight watchers or you subscribe to Hungry Girl, you may know about the Diet Soda Cake or Cupcakes. I tried it for the first time and the results were great!
You can use any cake mix, add 12oz. of diet soda, and 2 egg whites. Mix the ingredients together and follow the baking instructions on the box.
I made cupcakes using yellow cake mix and diet 7-up. I used Reduced Sugar Chocolate Fudge Icing. Each cupcake is 4 points with the icing. Without icing each cupcake is 2 points. You could use Fat Free Cool Whip instead of icing.
I've heard these are some great diet soda and cake mix combos...
Lemon Cake Mix and Diet 7-Up
Chocolate Cake Mix and Diet Coke
White Cake Mix and Diet Cherry 7-Up
Red Velvet Cake Mix and Diet Cherry Vanilla Dr. Pepper
White Cake Mix with Diet Orange Soda