These are packed with protein; just make sure your school doesn’t have a zero-tolerance policy on peanut butter, due to some children’s allergic reactions. Try this recipe:

1 cup peanut butter
1/2 cup non-fat dry milk powder or soy protein powder
1/2 cup raisins or chocolate chips
1/4 cup honey
Graham cracker crumbs

Mix all ingredients except the graham cracker crumbs in a large bowl. Shape mixture into 1-inch balls. Roll in crumbs and refrigerate (or freeze; balls will thaw by lunchtime).