GamingAllTheTime.com is running two giveaways right now, one for Killing Floor (PC / Steam) The other for E3 Swag! Check out the details for both in this link
http://gamingallthetime.com/?p=619
Http://www.original-gamer.com is giving away 10 copies of Serious Sam HD : The Second Encounter at:
http://www.original-gamer.com/?action=article&id=1265 you simply have to post to enter.