KIll people at Malfurion's breach.

At Malfurion's breach, there are a lot of people doing dailies obviously. Some of them go AFK now and then though, often guys that've done the dailies already, or people who've just stepped through the portal. For some reason they just sit there. 

There are also Emberspit scorpions at Malfurion's breach. These ones: Emberspit Scorpion - NPC - World of Warcraft

These little ****ers cast Ember pool. Ember Pool - Spell - World of Warcraft

So what you do to get people killed is simple. Round up a couple of the scorpions, 2-4 or whatever, and pull them up to where the npc's are. They don't kill them. Then just go stand on top of whoever is AFK, or reading a quest, or whatever. I think they also just cast these pools at people randomly, but not sure about that. You'll likely need to be a healer, or need one with you to do this, because they cast fireballs at ya too. They spawn quite fast if someone gets pissed enough to kill them, and they are easy to find. 

Some pictures: