K.C.
I usually do leftovers from dinner a couple of nights per week - pasta with meatballs, tofu, or chicken with rice and veggies. I have also done carrots and cucumber with hummus, chicken nuggets, pizza, etc.
In addition to one of the things above, I also give fruit and some kind of chips or crackers.
You can also do other kinds of sandwiches - egg salad, tuna, or chicken salad.