Not seen any posts reguarding this yet, not sure if it's known or not but it seems like a good way to keep farming xp for friends without them dying or just a plain hardcore normal group :P what it is, basically after general angerforges room leading into the golem room on the way to the bar (Everything was dead up to this point) I've not had time to test it but it seems pretty easy, kill everything on the way and there are 3 elementals, after killing one another respawns to take it's place.
I can imagine there might be questions for this so i'll wait and see if anymore detail is needed :P
http://img13.imageshack.us/img13/6535/brdelementals.jpg