Cook 1 pound italian sausage. Don't crumble it up, just cut it up as it cooks so it's nice and chunky.
Add about half an onion that's been coarsely chopped, a handful of sliced mushrooms, and a pressed clove of garlic.
After the onion and mushrooms have been sautéd in the sausage grease, dump in a 28 oz can of tomatoes -- whole, diced, whatever. You may want to add another small can of tomato sauce to thin the sauce out a little.
Crush some oregano and basil into the sauce. Add a teaspoon or two of sugar or a little wine or some grape juice to cut the acid taste of the tomatoes. Stew for a couple of minutes until it's perfect and serve over pasta.