Cut the spaghetti squash in half lengthwise and microwave for 9 minutes, face down on a plate. Depending on the squash, you may need to cook it longer than 9 minutes (additional 1-minute increments seem to work well).
While the squash is in the microwave, saute the onion in the olive oil until tender.
Add the ground beef and cook until no longer pink (breaking into pieces with a spatula as it cooks).
Add the 2 cans of tomato sauce to the pan along with the garlic, oregano, parsley, salt, basil and sugar.
Simmer the sauce for 10 minutes.
Once the squash is done and has cooled, remove the seeds and then shred the squash into a serving bowl.
Serve the meat sauce over the shredded squash (or over noodles for pickier eaters).