If you have kids in your life, this would be fantastic to make with them. In fact, you could probably just delegate the whole process to them, it's that simple. And, if you'd like to have a teaching element to it, go ahead and research why the ingredients in this cake make it work; you might be surprised at the science lesson you could get.
1 1/2 cups all-purpose flour
1 cup sugar
3 tablespoons unsweetened cocoa
1 teaspoon baking soda
1/2 teaspoon salt
1 teaspoon vanilla
1 teaspoon vinegar
5 tablespoons vegetable oil
1 cup cold water
Mix dry ingredients together in an 8x8-inch baking pan, or a 2 1/2-quart baking dish.
Make 3 wells in the mix.
Pour vanilla in one well, vinegar in another, and vegetable oil in the third.
Pour cold water over all and mix until well combined. Bake at 350F for 25-30 minutes, or until it comes back springy when you touch it. Allow it to cool and then sprinkle with powdered sugar. (Or you could spread chocolate frosting on top).