Try this one...
Wacky Cake
3 c. flour
2 c. sugar
1/2 c cocoa
2 t baking soda
2/3 c vegetable oil
2 T vinegar
1 T vanilla
2 c water
Combine dry ingredients. Make three holes: pour oil into one, vinegar into the other and vanilla into the third. Pour water ovall all and mix thoroughly. Pour into waxed paper lined 9"x13" pan. Bake 350 for 30 minutes or until tester comes out clean. When completely cooled remve cake from pan, and remove waxed paper. Wrap in foil and freeze if you want to use it at a later date.