Just about every school day since Jack started first grade I've made him the same thing for lunch: a peanut butter sandwich (no jelly), cheddar cheese goldfish, and a few cookies (lately Oreos). For a while I included baby carrots, but he confessed that he didn't eat them so I stopped. He now eats baby carrots under supervision at home.
The only exception was when the elementary school cafeteria served pizza, which happened two days a month. Now that he's in junior high? He eats the same thing. Every. Single. Day.