PS: Da pra farma o super pet haxor mini-phoenix!!!
Requirement: A party with a warlock
Note: only works for instances in normal mode (can't reset heroics)
For example, you want to farm Kael'Thas in MT, either for the pet or just for easy shards / voids, or even for rep.
Since you're going to farm it several times, get a group together that won't leave after one run. What you really need is a warlock.
How you will proceed:
1. Clean the instance once (including Kael)
2. Gather your party in the stairs just before KT's room
3. Start summoning everyone in your party, including yourself (if you are the warlock)
4. Once everyone has been summoned, all head towards the orb in KT's room and click on it (which teleports you outside the instance)
5. Once everyone is outside, reset the instance.
6. All accept the summon.
You will now be in a new instance, but in the stairs before KT's room. Now there's only one thing left to do: kill the trash pack (your warlock will be able to make 5-6 shards, so shards are not a problem if you want to farm the boss for a while), and kill KT.
This was just the example of Magister's Terrace. But it's applicable to every single instance in the game.
For other instances, it's better to have a mage with you, so can make a portal to shattrath (or whatever) after the summons are done, otherwise you might have a problem exiting the instance quickly enough.
Enjoy it while it lasts.
Edit: Apparently you don't even have to bother about the instance reset timer (5 per hour), getting summoned into the instance bypasses the limit too. So this is basically endless farming, without any break. o.O
