In 12-inch skillet, cook beef and sausage over medium-high heat 5 to 7 minutes, stirring frequently, until beef is thoroughly cooked and sausage is no longer pink; drain.
In 3- to 4-quart slow cooker, mix beef mixture and all remaining ingredients except spaghetti and Parmesan cheese.
Cover; cook on Low heat setting 8 to 10 hours.
About 20 minutes before serving, cook and drain spaghetti as directed on package. Serve sauce over cooked spaghetti. Sprinkle with Parmesan cheese.