Grim Batol and Halls of Origination.
Grim Batol, once one of the greatest dwarven fortresses, is now home of the Twilight Hammer and the corrupted Black Dragonflight after the battle between the Wildhammer and the Dark Irons. The 5-man dungeon lies to the west of the Twilight Highlands. Players can enter the dungeon on Normal-mode at level 84, requiring minimum ilvl 305 to queue up. The dungeon is notable for having players ride dragons as vehicles over the extensive trash, bombing them to get them to low HP. With the numerous dragons as trash, it's also an excellent place for skinning.
The Halls of Origination, are part of the Titan research facility of Uldum. Along with Ulduar and Uldaman, it was used by the Titans thousands of years ago. Unlike the other two, the Halls' purpose was not to be a prison--it was used for research and development of new races. One of those races was the Tol'vir - a mix between humans and cats, most of which populate the other Uldum dungeon, the Lost City of the Tol'vir, where it is rumored that a deadly secret is hidden.
We hope you all have fun!
The Dev/Test Team