Here's a low-fat version of manicotti courtesy of Jessi. I grabbed it from her on the go, so it comes without measurements and without herbs and spices. I'll leave those things up to your ingenuity.
--Manicotti Shells, cooked al dente
--Frozen Spinach, thawed and drained
--Low-fat Sour Cream
--Fat-Free Small-Curd Cottage Cheese
--Shredded Parmesan Cheese
--Salt and Black Pepper
--Low-Fat Mozzarella Cheese
Preheat oven to 350 degrees Fahrenheit. While the pasta shells boil, mix the drained spinach, cottage cheese, sour cream, and shredded Parmesan cheese in a bowl. Add salt and pepper to taste, plus any spices or herbs that you prefer (oregano, basil, parsley, etc). When the manicotti shells have been drained and are sufficiently cool, spoon the spinach and cheese mixture into them. Place the stuffed shells in a baking dish, pour tomato sauce over and around them, then top with mozzarella cheese. Cover with aluminum foil and bake for 45 minutes. Remove the foil and bake for 10 more minutes.