ArenaNet’s announced a surprise beta testing for the Guild Wars 2 beta for this coming Monday.
The stress test will happen from 2pm EST (7pm BST) and go on until 9pm EST (2am BST on Tuesday).
The test will only be for pre-purchasers, but players can use the same character it used in the first beta testing weekend in the same client.
More details here. Guild Wars 2 is expected to release sometime this year.