In a large skillet (or in your slow cooker if you have the saute function), add the sausage and ground beef. Cook and crumble the meat using a spatula or meat masher. Drain the fat if desired.
If using a skillet, transfer the ground meat to your slow cooker. Add the rest of the ingredients (except the spaghetti). Cover and cook on high heat for 4-5 hours or low for 8-10 hours.
Cook pasta according to package instructions. Serve sauce over pasta.