- delete your current account and create a new one (afaik you need a new e-Mail adress then... if the old "change mail to something gibberish/weird" way won't work, of course)
- changing a username isn't that easy, you can earn this honour by solving 250 (subject to change, due to the overall growing amount of) quests. Then ask an admin.
Note: most likely the MMO's (if you play any of them) won't make the change, so your lost your progress there... results in a restart.