Free trials are back! ArenaNet has partnered with several gaming sites to give away a massive amount of free trial keys for those that have yet to check out Guild Wars 2. Each site will begin giving away the keys on April 15th, so be sure to check back then! The keys will be used for the following weekend - April 19-21st - so make sure you get your client downloaded before then.
The Guild Wars 2 free trial weekend begins at 12:01 AM PDT on Friday, April 19, 2013 and ends at 11:59 PM PDT on Sunday, April 21, 2013.
Here's a link to all of the sites giving away keys. If you find more, please respond to the thread so we can add them!Here's an official post from ArenaNet, wherein they mention that those that participated in the last free trial are able to participate in this one by using their old login information.
Your former free trial account will be active for the April 19-21 event—to prepare, just update your game client by double-clicking the Guild Wars 2 icon on your desktop, or go to https://account.guildwars2.com/and sign in to download and install the game again!