I don't know exactly what's so funny about this long chatlog between some of the more popular undead and evil NPCs of the game (maybe just how similar this crowd ends up being to us), but it is hilarious. Basically a sequel to the old boss chat, this one has "theLichKing" chatting with "Killzone'jaeden" and "An00barak" about everything from how cold it is in Icecrown to just where Sargeras is from. Very well done, Warraven of Ravenholdt. He even gets some nice lore in there even between all of the pony jokes.
And this little chatlog reminded me of all the funny stuff over at Wowbash. If you've never looked through the archives over there, definitely check them out, but be careful. Browsing all of those funny quotes is almost more addictive than actually playing the game.