(Easy to make and always tasty! However it's not something for a formal occassion.)
1 box yellow cake mix
half pint (8 oz) sour cream
1/4 cup cooking oil
1 cup sugar
Mix together yellow cake, sour cream, cooking oil, and eggs in a bowl.
Pour half the mixture into a 13x9 pan.
Combine the cinnamon and sugar and sprinkle over the cake.
Pour the rest of batter over the first layer.
Bake at 350 degrees for 1 hour.