In a small pot add the water, sugar, ginger, cinnamon and allspice. Bring to a boil over medium heat, stirring to dissolve the sugar, then lower the heat and simmer until slightly thickened. Remove from heat and strain into a bowl. Refrigerate the syrup until cool. Pour the syrup into a blender and add the frozen orange juice, molasses, ice cream and milk. Blend until smooth and serve.