One of my college acquaintances was in town for the weekend and invited my husband and me to dinner at Dukem over on 12th and U. We took advantage of Dukem's outdoor seating and spent several hours eating, catching up, and enjoying the abnormally cool nighttime air. Although I've eaten Ethiopian food once before, the first time was not as memorable as the second. Dukem's menu, and Ethiopian food more generally, consists of spicy, tangy stews (lamb, beef, lentils, and/or other vegetables) with various combinations of cardamom, dried chilies, garlic, ginger, onion, other spices that I probably can not identify, and butter (I would imagine it's clarified). The highlight for me was probably the injera -- a spongy, tangy, flatbread that is used in place of utensils to sop up all the juices from the entrees and side dishes. It was much more flavorful than the grey color would suggest.
While I can't speak to the authenticity of Dukem (I simply don't have much experience with Ethiopian food), I can say that the food here is tasty and a great way to catch up with old friends -- it comes out in large platters for sharing and you get to eat with your hands. Try the lamb wot (lamb stew), lentils, wide variety of Ethiopian beer, and fried fish (can't really go wrong there): http://www.dukemrestaurant.com/menus.htm.