Fun, colorful fruit salad
Combine orange or grapefruit slices, banana circles, grapes, diced apple or pear, and nuts like chopped walnuts and sliced almonds into a portable container that your child can carry to school. Add in two tablespoons of fruit juice to give the salad a bit more flavor.
It's possible to use low-fat yogurt instead of the fruit juice, but, if you do, the suggestion is for the salad to be refrigerator--not always something that can be done in a school setting.
Drop a low-fat granola bar into the sack and send along a thermos of skim milk.