3 cups uncooked rigatoni or large tube pasta (or really any pasta that you have in the house. :))
1 lb bulk Italian sausage (I usually only use 1/2 lb)
1 cup finely chopped onion
1 can (14 1/2 oz. ) Italian diced tomatoes, undrained
1/2 pkg (10 oz) frozen spinach, thawed and drained
1 pkg (8 oz) cream cheese, softened
2 cups shredded part-skim mozzarella cheese, divided

Cook pasta according to package directions.
Meanwhile, cook sausage and onion over medium heat until sausage is no longer pink; drain.  Stir in the tomatoes, spinach, cream cheese and 1 cup mozzarella.  Combine pasta and sauce.  Transfer to a greased 11 in x 7 in. baking dish.
Cover and bake at 350 degrees for 35 minutes.  Uncover; sprinkle with remaining cheese.  Bake 10 minutes longer or until cheese is melted.