NCsoft has announced that a new Guild Wars add-on is currently in development. Technically it's not even an add-on, since you can play it on its own, but if you have both it and Guild Wars you'll be able to explore both game worlds and you'll get some new toys in the old one too.
Guild Wars: Factions will introduce all sorts of new features, including new regions, professions, skills, missions and monsters. There will also be expanded options for both co-op and Player-versus Player gaming, and a host of new features for guilds. You won't need the original Guild Wars to run Factions, either.
The game isn't out for a while yet, but Guild Wars players from around the world will get the chance to try it out during the January 20-22. That's when ArenaNet will open its servers for the Guild Wars: Factions Global Free-for-All PvP Weekend, don't you know.
If you take part in the event you'll be able to try out two new professions - Assassin and Ritualist - and have a go at using their deadly skills/arcane spells.
Plus you'll be able to familiarise yourself with the new PvP content, Battle Isles, which is said to offer "new PvP experiences, new and expanded arenas, new quests and a new explorable area as well."
And finally, you can try out the new Observer Mode. This allows players to watch battles unfold, even if they aren't taking part, and see what strategies and tactics are being used.
Guild Wars: Factions is out this summer.