1 box graham crackers
1 lg. box vanilla instant pudding
1 (8 oz.) carton sour cream
1 can chocolate icing
3 c. milk
1 (9 oz.) container Cool Whip

Line a 9 x 13 inch pan with whole graham crackers. Prepare pudding with 3 cups milk, then add sour cream and Cool Whip; mix well. Pour 1/2 mixture over graham crackers, then add another layer of graham crackers. Put remainder of mixture over this. Add another layer of graham crackers; top with 1 can icing. Let set in refrigerator for 3 hours before serving.