depending on what they like here are some of our faves:
Zucchini: Grate 2 large zucchini and set aside. Peel and slice two cloves garlic and heat through gently in a pan with a good 4 tbsp of olive oil in (from cold). When beginning to sizzle, add zucchini and warm through (not browned), for about 5 minutes. Sprinkle with a few chilli flakes, then stir into cooked pasta shells/twists and add loads of finely grated parmesan and a twist of black pepper.
Bean & salami: Cut a pack of salami slices into shreds using kitchen scissors (it's faster). Peel a clove of garlic and slice into a pan. Add salami. Turn on heat and wait for the fat of salami to come through slowly and coat garlic, Stir frequently. Low heat. Then add a can of chopped tinned tomatoes, a bay leaf, and a tin of drained cannellini beans, plus about half of the tomato tin of water too. Turn heat up until bubbling quite hard, for about 15/20mins or so, until reduced. Season to taste if needed. Serve with small shape pasta (ditalini, maccheroni etc are best).
Tuna and tomato: Make a basic tomato sauce recipe (sliced garlic cloves into gently warming olive oil), tomato tin added once garlic is clear but not browning. Bay leaf. Basil leaves or dried oregano if you have it. Cook uncovered for about 15mins. Add splash of red wine for flavour (not necessary but nice!) and then a tin of drained tuna. Stir through and cook for further 10mins. You can even set aside some for your kids, then add capers and black olives to remaining sauce to jazz it up for the adults (if kids don't like those extras). Goes well with any pasta and a sprinkling of cheese.
Tip: even when I only make a basic tomato sauce, I always make much more than I need (usually 2 or 3 tinned tomatoes worth ) and freeze the remainder, even into small portions for the kids, or larger family portions.