I don't play WoW, but I do play EverQuest 2 and had an Esperanto-related experience there. In this game there is a guild window with information about members of our guild and so on, including a space where each person can write a brief line of whatever they want under their character's name. Most of my guildies put a little joke or something cryptic there; I put "Cxu vi parolas gxin?" and someone else in the guild recognized it as Esperanto. Turns out they had studied it ~10 years ago heh.