Not sure if this is common knowledge, but Death Rifts that start by you having to clear the first 4 Wolves by clicking the stones and killing them next to the stones can be used to non-stop grind.
If you stand in the middle of the rift, the 4 wolves will spawn and if you keep killing them in the middle and not at the stones, they will spawn non-stop. The rift will keep resetting at 15 mins and wont go away either.
After you kill the 4 wolves takes about 2 seconds for the next 4 to spawn, great for any AOE damage. I did it with a healer and a Ranger casting AOE Arrows, and leveled really fast.
EDIT: You can move from different level rifts of course, whatever you or your group can handle. I went from 46 to 50 this way in a couple of hours. The experience at first doesnt seem great. Think I was getting about 350 exp per wolf x4 which is 1400. Killed 4 every 15 seconds which is 5600 XP every minute. Which is more than the average quest at that level. Which means you are basically turning in a quest less than every minute. And you can basically watch TV while you press the same 3 buttons over and over.