1. Preheat oven to 350°F.
2. Grease small baking pan.
3. Cut squash lengthwise in half; remove seeds.
4. Place halves, cut side down, in baking pan, bake 30 minutes.
5. Turn squash cut side up.
6. Place half of margarine and brown sugar in each cavity.
7. Bake 15 minutes longer or until squash is fork-tender and margarine and sugar melts.