Alienware Arena is giving away free Steam coupons good for 50% off Painkiller: Hell & Damnation. The game is currently on sale for 33% off, so after you stack the 50% off coupon it ends up being $6.79 (66.6% off). I believe this is an updated version of the original (and best IMHO) Painkiller game.
The offer expires in 20 days.
See more details at the offer page here.
Here’s a free Steam coupon code up for grabs: HGFTX-J7I22-BPN0R