Found this little gem on another forum:
Mate, just do it once, extend your lockout in it every day, and it practically minimizes the chance you ever get it as a random again :P Using this method, I've made Azjol Nerub my daily dungeon 12 out of the last 13 times :P
Dear god why havent I thought of extending my lockouts on dungeons I hate doing. All that wasted time arrrgh!!!