1 and a half cups unbleached white flour
1/3 cup unsweetened cocoa powder (hot cocoa mix works too... ;)
1 teaspoon baking soda
1 cup sugar
1/2 cup vegetable oil
half a cup cold water
half a cup of grape juice
2 teaspoons vanilla extract
2 tablespoons vinegar

Preheat oven to 375 degrees.
Sift dry ingredients into 8" square or 9" round baking pan. Mix liquids (except vinegar) and whisk into the dry ingredients. When batter is smooth, add vinegar and stir quickly, until it is evenly distributed. Put it in the oven, don't let it stand around (The vinegar and baking soda react to make the cake rise - BOOM like that volcano you made for science class in grade school.)
Bake for 25-30 minutes... or longer until done.

Peanut Butter Icing: Here's what I did, because it's what we had on hand - I mixed peanut butter and corn syrup (left over from a gingerbread house making session...), with just a handful of flour, until it was the consistancy I wanted. Turned out pretty good. My roommate was horrified to discover she was eating corn syrup and enjoying it. (She hates the stuff ;)

Chocolate Icing: Here's what I would have done if I'd had the ingredients - 3 parts powdered sugar to one part baking cocoa powder. Add water just a teaspoon at a time until you get the consistancy you want. I like it thick, mom likes it to be runny for drizzling.