15 minutes of prep, then leave it to your slow cooker to do the rest! You'll return home to a thick, rich meat sauce to top your pasta.
In a large nonstick skillet, brown the beef and sausage. Using a slotted spoon, to leave the grease behind, transfer the meat to the slow cooker. Pour excess grease from the pan, and return to stovetop.
Heat the olive oil in the skillet over medium-high heat. Add the onions and peppers and saute for 3-5 minutes, until beginning to soften. Add garlic, and saute for one more minute. Do careful not to burn the garlic.
Add the veggie mixture to the slow cooker, and then add the remaining ingredients (tomatoes through brown sugar). Cover and cook on LOW for 8-10 hours.
Adjust seasonings to taste. Serve hot atop cooked pasta with shredded Parmesan.
If you'd rather make this on the stovetop, use a large sauce pan instead of transferring everything to the slow cooker. Saute the meats first, then the onion/pepper/garlic mixture. Add the remaining ingredients. Cover partially and simmer over low heat for 30-45 minutes, stirring occasionally.
No-meat version: Just make the sauce as is, from the onion/pepper/garlic step forward.
Meatball version: I often make meatballs separately, then simmer them in the sauce, instead of adding meat directly to the sauce.