Ask a grown-up to help you bring the water and butter or margarine to a boil in a medium-size saucepan. Turn off the heat and stir in the couscous, raisins, and sugar. Cover the pan and let it sit for 5 minutes. Fluff the couscous with a fork and scooop it into 4 bowls. Pour a little hot milk on top, and eat. Serves 4 people a Tunisian-style treat.