The Guild Wars 2 Facebook Page has word that ArenaNet is conducting another stress test for Guild Wars 2 tomorrow (thanks nin). Also, the Guild Wars 2 Website has a list of the game worlds that will be available for the game's head start later this month. Here's word on how you can help them stress out over their MMORPG sequel:

We will be conducting a stress test tomorrow Wednesday, August 15 from 12:00 Noon PACIFIC Time to 4:00 PM PACIFIC Time.

We will be actively working on the game during the event, so you might experience connectivity problems or discover features that are not working as designed.

Any issues you experience are a result of the rigorous conditions of the stress test, and are in no way representative of the state of the game at launch.

By participating in this stress test, you’re helping us make Guild Wars 2 a better game. Thanks for your cooperation—we’ll see you in-game!
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Please note:
* The stress test is open to anyone who has pre-purchased Guild Wars 2.
* Characters will not be wiped from the previous Stress Test.