Hey, I don't know if it's the good area to post it, but a friend recently show me this site.

Many pre-order games are at -15% off and there is some -20% vouchers like these 3:
20SUM-MERSA-VINGS or
SUNNY-SAVER-20PEC or
20PEC-FACEB-SAVER
(1 per purchase I think)

So, for example you can get RO2 for like 34$ or Dead islands / deus ex for the same. There is other steam registerable games like: DNF, magicka, mafia 2,...

(maybe they'll add in few time SKYRIM and RAGE)

You can get a 5$ gift after your first purchase if you register as a referal:
http://www.greenmangaming.com/?gmgr=kozufegi

or (without referral = without 5$ after first 5$ purchase):
http://www.greenmangaming.com/

I think it's a good deal, and i like to share it.