Milk stout (sometimes called sweet stout) is an interesting variation on the stout theme - a stout brewed with lactose to make it sweeter. Lactose is unfermentable by the types of yeast used in beer, so it remains in its sugar form, rather than being processed into alcohol. I attempted to brew a milk stout a couple of years ago, and failed miserably. I'll stick to buying the commercial varieties for now, until I get brave enough to try it again.
Left Hand Brewing Company is located in Longmont, CO, and they produce a lot of different varieties of beer. In fact, when I looked in the fridge tonight, I had 3 different Left Hand brews waiting to be tasted. I had burgers for dinner, so I decided on a dark beer to go along with my red meat. Left Hand's Milk Stout poured a deep brown that was nearly black, with a small tan colored head. Mouthfeel was lighter than I expected, and also more carbonated. The aroma is mostly roasted malt, and the flavor is roasted malt, chocolate, coffee, and a hint of licorice. It had the expected sweetness from the lactose. Some brewers add additional sugar after pasteurizing, to increase the sweetness, but I don't believe that's the case with Left Hand's version. This was a very nice milk stout, and I wouldn't hesitate to buy it again.