Heat oven to 400° F. Scrub outside of spaghetti squash and puncture  3-4 times with a fork. Place squash in a shallow baking dish with 1/4 cup water. Bake for up to one hour; a fork will easily pierce the outer skin when done. Cut open squash, throw out seeds, and scoop squash into serving dish; season with olive oil, salt and pepper, and diced garlic.