The original Guild Wars, Nightfall and Factions are collected into a nifty bundle at Steam and are on sale today only for $14.99 as part of Steam's Summer Camp promotion running from now through July 10th. As a bonus, Eye of the North is also half off and can be had for $9.99. What a great way to prepare for Guild Wars 2 by taking the original game's "refresher course"!
Find out more on the Guild Wars Steam promotion page.