From www.guildwars.com

Today's press release announces the upcoming Guild Wars Nightfall World Preview Event, which will take place the weekend of September 22nd. The event will offer you the first opportunity to create Nightfall-specific characters from the core professions as well as the Dervish and Paragon, to try out new Nightfall skills, to explore one of the provinces of the new realm of Elona, and to test your mettle in two new arenas. You'll even get a chance to view some Nightfall in-game cinematics! So, get ready for three days of solid Nightfall, starting September 22nd at 12:01 a.m. PDT!