CoD Nazi Zombie fans may be interested in our 69.28.220.119:28961 DaDs server. The zombieX mod takes the Nazi zombie co-op mod and puts it on a dedicated server where one side is human, and the other is Nazi zombie. You can puke, call in zombie dogs, and do a few other fun things like switch between FPS view and 3rd person view. Be sure to click the quick chat button, which is B by default, and look at the zombie options for the mod once you connect.
More information on the mod can be found in our forum in this thread.