Cook pasta according to package directions. Drain and set aside.
In a large skillet, cook ground beef, bacon and sausage over medium heat, stirring to break up beef and sausage. Drain fat. Add meat mixture to cooked pasta.
In another skillet, heat olive oil over medium heat. Add onion, green peppers, mushrooms, garlic and Italian seasoning. Stir to combine. Cook for 5 to 7 minutes, until veggies are softened. Add veggie mixture to cooked pasta.
Stir pizza sauce and pepperoni into pasta mixture. Stir to combine everything. Spread into a 9x13 inch casserole dish.