Tacos, burritos, enchiladas, etc. They are all easy to make.
Chili, spaghetti, etc. These are nice in the winter as they are a bit more filling and substantial. Chili can be made at home and just heated up at the campsite. You can make your own spaghetti sauce at home beforehand also if you don't like jarred.
Soups - again, can be made at home and heated at the campsite. Nice chunky soups for cold weather camping. Bring some french bread and heat it up to go with the soup.
Grilled cheese sandwiches - they're so simple but a lot of folks don't think of them for camping. Add tomatoes, mushrooms, ham, and so on for a more filling sandwich.