Prepare pasta according to package directions, drain and set aside. In a large pot combine the sauces, pepper, mushrooms and olives. Heat until hot but not bubbling. Slice pepperoni pieces in 1/2 and add to sauce. Remove from heat and combine with pasta. Pour into an 11 by 13-inch baking pan. Combine the cheeses and sprinkle over pasta. Bake in a preheated 350 degree oven until cheese is melted and sauce is bubbling.
Recipe courtesy Young Chef's Cookbook 2000