This is a favorite when I take it to a carry-in:

ULTIMATE CHOCOLATE CAKE

1 devil's food cake mix
1/2 c. cocoa
3 eggs
1 c. real mayonnaise
1 1/3 c. water

Blend all together and beat well for 3 minutes. Pour into 2 9-inch or a 9x13 inch pan which has been greased and floured. Bake at 350 degrees for 30 to 35 minutes (9-inch) or 40 minutes (9x13). Frost with chocolate frosting.

3 oz. cream cheese
1/2 c. butter
1/2 c. cocoa powder
1 tsp. vanilla
5-6 T. milk
4-5 c. powdered sugar

Combine all ingredients except sugar and mix until creamy. Add powdered sugar until mixture reaches a good spreading consistency.