I try and plan my day around my life....so when I know I'm going to be up late, I always try and leave some Points (or calories in your case) to have a small snack. When I don't manage to make that happen, I take the calories away from the next days total. If its midnight, technically its the next day anyways
My midnight snack is normally low-fat yogurt, as it helps me not feel hungry but it also doesn't upset my stomach. An apple or some carrots does the trick too.