HD: Greenmangaming 20% off (Red Orchestra 2 $27, DDE $33, Deus ex $34)
20% coupon - SUNNY-SAVER-20PEC or 20PEC-TWEET-SAVER or 20PEC-FACEB-SAVER (they do not stack).
Some great deals, if you haven't already bought via steam both Deus Ex and RO2 are Steamworks games, so you'll get a key to d/l from therre and it's the cheapest you'll find either game.
Ro2 regular edition is 27.16, Deluxe version (which gets you into beta before release) is 33.96.
They also have From dust at 11.95, but no coupons work with it (still cheaper then steam by far).