Preheat oven to 375°F (190°C). Cook pasta according to package directions. Drain and set aside.
In a large skillet, brown ground beef over medium heat. Drain off any excess fat. Stir in tomato sauce, oregano, garlic powder, salt, and pepper. Bring to a simmer and cook for 10 minutes.
In a large bowl, combine cooked pasta, meat sauce, and ricotta cheese. Mix well.
Pour the pasta mixture into a greased 9x13 inch baking dish. Sprinkle with Parmesan cheese and mozzarella cheese.
Bake for 20-25 minutes, or until the cheese is melted and bubbly.
Let stand for 10 minutes before serving.
Notes
For a richer flavor, add a layer of sauteed vegetables (onions, peppers, mushrooms) to the meat sauce.