1 1/2 lbs. hamburger
1 med. onion, chopped
2 cans Ragu chunky pizza sauce mix
2/3 pkg. rigatoni noodles
3 lbs. Mozzarella cheese
Olives, peppers, mushrooms - optional
Pepperoni

Brown hamburger and onion together and drain. Mix in sauce mix. Make alternate layers in crock pot, starting with meat sauce, noodles, pepperoni and cheese. Cook on low for 5 hours.