Unexpected – but welcome – addition in 5.0.4 is that you can now queue for Battlegrounds and Dungeons at the same time.
DPS players, rejoice!
UPDATE: Oh, hey! You can queue for everything ALL AT ONCE!
Aw yeah. I’m going to sit around Dalaran and WAIT in several lines AT ONCE.
Cynwise's Warcraft Manual 
Just don’t be on a flightpath when one pops, because you can’t enter the instance/BG/whatever until you land. I found that out the hard way last night.
LOL!!! Dude I laughed so hard reading that last line. Thank you for that! 🙂
Nice! No longer do I have to choose what I want to wait 30 minutes!