I was running a guildy through rfk and I noticed at the end of the instance where you go up that vine theres a cooking pot. I decided to jump on it and found not only that i didn't fall down but also if you look at it a certain way its a blue matted screen.Random exploit.
Theres another exploit in Darkshire. On the roof left of the alliance flight master theres a chimney. If you run jump on to some air pockets on the south of the chimney you can get into it eventually.Takes a lot of work. Make sure you hearth is up when your try it once your in it you get stuck,auto unstuck didn't seem to work for me.Maybe it will for you.
Also this probally has been mentioned but theres an exploit in stormwind, where you can jump on air pockets by a candle and fall under stormwind. Ti get out I think you have to hearth.Could be wrong.
ANd last but not least theres is an exploit where you can fall under orgimmar. Its a bt of work though but basically you jump on the left fence buy the pet trainer, go all the way up the pole to your left. Jump on the roof straight ahead of you and jump over the fence.
To get out avoid the red matted flooring and go to the right, it will take you to the entrance of org, where everyone duels.