O.K. No one has added any, so I'll give some more adolescent friendly, protein snacks
. Pizza quesadillas, which you can make by spreading pizza sauce, mozz cheese, and pepperoni (or whatever you son likes on pizza) on the inside of two flour or wheat tortillas, then heating in a nonstick pan, until the cheese melts. Chicken and biscuits with gravy, which you can make by cutting boneless chicken breasts into biscuit-sized chunks, dredging in flour, salt and pepper, frying, and putting between a biscuit. You either can make the gravy from the pan drippings or you can buy a dried instant gravy packet that just needs hot water added to it. Fruit smoothies with plain yogurt added (the recipes for these are endless). Sugar free milkshakes, which you can make by using milk and Healthy Choice "no sugar added" ice cream. Queso and chips, which you can make by heating Velveeta cheese and tomatoes with peppers in the microwave until the cheese melts, stirring, and serving with tortilla chips.
O.K. That ought to do it. 
lillian,
I am coming over to your house for snacks. YUM
We do mainly cheese sticks, yogurt and hard boiled eggs. I have to watch how much they snack because my children won't eat dinner if they eat too much and too close to dinner.