Haven't seen this posted yet so here you go taken directly from steams site.
Not my kind of thing but a good thing for some MMO addicts!Most of Steam's Massively Multiplayer games are on sale through the 19th, starting today. Get Sony's EverQuest II The Shadow Odyssey for 75% off this weekend, (then 30 days free play for new subscribers).
There are other great deals too, EVE Online and Conan are 50% off. And with no subscription fees, you can get a whole lot of Guild Wars with Trilogy at 20% off.
Check 'em all out here.