Okay well recently at the "Games Day" event in Baltimore came a onslaught of information about the new expansion coming out next month. Here is a offical trailer:
http://www.youtube.com/watch?v=BftsumwX1FQ

Along with a presentation of how the expansion is, how it works and how the Open RvR dungeon will work.

Part 1:
http://www.youtube.com/watch?v=idkpRUDDStw

Part 2:

http://www.youtube.com/watch?v=6X-FlC9Te3c

Part 3:

http://www.youtube.com/watch?v=ldrkYGqY-D8