Pumpkin Spice Cake

1~18 oz package spice cake mix
1~15 oz can pumpkin
3 eggs
1/3 cup canola oil
1/2 teaspoon cinnamon
1/3 cup water

Combine the cake mix, pumpkin, eggs, oil, cinnamon and water in a large bowl. Set mixer on the medium setting to blend the mixture well for 2 minutes. Pour the batter into a 9x13 greased baking pan. Bake at 350 degrees for 30 to 35 minutes, or until a toothpick inserted into the center comes out clean. Top with frosting of your choice or serve with cinnamon ice cream.