Bring a large pot of lightly salted water to boil. Pour in rigatoni, and cook until al dente, about 8 to 10 minutes. Drain, and set pasta aside.
Meanwhile, brown ground beef and italian sausage in a large skillet over medium heat. With a slotted spoon, remove beef and sausage to a baking dish. Stir mushrooms, spaghetti sauce, and cooked pasta into the baking dish. Sprinkle cheese and pepperoni over the top.
Bake in preheated oven until the cheese is brown and bubbly, about 20 minutes.