Preheat the oven to 400.
Cut both of the squash lengthwise and lay open/seed side up on a baking sheet. Drizzle with olive oil and sprinkle salt and pepper on top. Bake in the preheated oven for 1 hour, or until soft.
In a large skillet, brown the Italian sausage with the chopped onion and diced green pepper. Once browned, add the olives and spaghetti sauce.
When the squash is soft, scoop out the seeds and insides. Then gently pull apart the "noodles" before adding the sausage stuffing. Stuff each of the squash with the sausage mixture. Top with a few pinchfuls of shredded cheese. If the cheese doesn't melt, put back into the oven for 5-10 minutes, or until cheese melts. Remove and let cool slightly before serving.
Serve Pizza Stuffed Spaghetti Squash, as is or with side of bread.