Due to the success of the 75% off ($5 in the US) Killing Floor sale last week, Valve has brought the sale back for one more day. Until noon tommorow you can get Killing Floor for 75% off. If you know any friends looking to get KF, or want to get KF for someone as a gift, now is the time. It will be a long time before you have another chance to get KF at these prices.
Head over to the Killing Floor Steam Store page now to get the game.