In a medium bowl combine the flour, sugar, cocoa, soda, and salt--stir to mix well.
In a large bowl combine water, oil, vinegar, and vanilla. Dump the dry ingredients into the water mixture and stir with a fork until smooth. DO NOT BEAT. Pour batter into an UNGREASED 9x13 inch pan.
Bake at 350 degrees F (175 degrees C) for 35 to 40 minutes.
