I often just do a basic tomato sauce for with pasta - fry some onions and garlic in a little oil, add a tin of tomatoes, a bit of tomato puree, a dash of balsamic vinegar, some herbs and pepper (OH and I salt ours on the plate), cook to reduce it a bit. Sometimes I chop some courgettes or other veg and add that too. The kids prefer it blended to a smooth sauce when there is veg in there, as do I actually.
Quickest and easiest when I'm being lazy is to soften some onions then add a big dollop of soft cheese (like Philadelphia), stir to melt then add a little cream or milk and stir again. You can add herbs if you want, or start off with cheese with herbs in it. You can add some grated cheese too, just watch salt content with all the cheese.