The India Tree Gourmet line of dark sugars is yours for the grabbing at Berkeley Bowl. My favorite is the Dark Muscovado, jam packed with molasses. It's also a real ding in any perceived aura of locavorism - hauled in from Mauritius. The Bowl has carried this stuff for years, but I don't get over there much these days.
I've been using the sugar like a philistine, i.e. just like anyone would use any sugar. Particularly as the basis for simple syrup in Sazeracs.