It might be fixed with this maintenance but yesterday it's still been working.
(EDIT: This is in Gorgron Zone of course)
If you are on the Rexxar questline and you are at the part where you have to return an artifact/relic Magmaron relic or something I believe it was called, you fight alongside Rexxar against Gronnlings and Gronns and then some Orc to collect the Questitem. The Gronnlings give you nearly 4000 experience every kill. So you can reset the quest/event and kill them over and over and over. Killing 3 of them gives you as much experience as a quest.