Nothing like some meat sauce to punch up your pasta!
In a big saucepan, combine the beef, onion, garlic, and green pepper. Cook and stir that stuff until meat has browned and vegetables are tender. Drain out the grease.
Stir in the diced tomatoes, tomato sauce, and tomato paste. Season the sauce with oregano, basil, salt, and pepper, and let the whole thing simmer for 1 hour, stirring occasionally.