Here is a small find I came upon when pimping out some farming alt accounts. Did a search, didn't find anything on that matter here. You can end up being in the non-twink (exp-on) queue while having your experience technically frozen for 10 days. Here is how I did it:
1- Make sure you have one pimped out character, with MOP gear. One valid reason could be to solo farm instances for money, which is what I do via botting.
2- Upgrade the account to the 10-day Cata trial
3- Queue in BGs
The fun thing with this one is that while the trial still allows you to gain experience, but it prevents you from leveling up. It keeps you one point away from level 81, but you still technically gain experience points for quests, killing mobs, and BG objectives. And, you also get queued in experience on BGs.
Meaning your pimped out Paladin will have a whopping 300k and will easily kill anyone. Or that you will one-shot anyone with that fire Mage.
Perhaps this could have more potential uses, but abusing a bunch of poor 80-84's seems to be the main use of this little trick. Sure, it won't last forever, but when you use cheap accounts to usually farm, this can prove to be some fun entertainment.
Enjoy!