Drain and rinse the pasta with cold water, and set aside.
Heat the olive oil in a sauté pan over medium-high heat. Add the garlic and onions and cook until translucent. Add the olives, peppers, mushrooms, and tomatoes, cooking until vegetables reach desired doneness. Add the oregano, season with salt and pepper, and mix in half of the cheese.
Stir the pasta into the sauce to heat the noodles. Once heated through, top with the remaining cheese and serve.