Over medium heat, heat water and sugar in a saucepan, stirring occasionally until the mixture reaches a boil. Boil for an additional 5 minutes. Add cranberries to the sugar mixture, and stir until the berries begin to pop. Heat until the berries have broken down enough to reach a consistency of your liking (the longer you boil, the fewer whole intact berries will be in the sauce.) Pour into a bowl and chill. May be made 24 hours in advance.