- Orgrimmar & Ironforge: Earth and Fire rifts
- Thunder Bluff & Stormwind: Water and Wind rifts
I may have time later this week to map those quests out, but not tonight, alas.
Things I wasn't sure about until I did it:
- You do not need to be in a raid to get the buff.
- You get the buff when the elementals stop spawning (i.e. when the rift closes).
- The buff hits an area of people, so you need to be nearby when the rift closes.
- You can (and probably will) get both buffs in one city defense event.
And then after the event you can queue for the specially available bosses. (LFD or the portals in the city.)