While flying through Icecrown a while back, I found this doodad floating in the air.  It’s a circle of chairs in the air, which has since been removed.  I wasn’t able to click on or sit on them, but they were there and even got a name when they were moused over, “Doodad_GeneralChairLoEnd02″.
Seen any other weird bugs or things floating around?  Given the enormity of WoW, I’m surprised there isn’t more stuff like this.