2K Games and the folks at Humble Bundle have joined forces with what can only be described as a massively lucrative bundle deal. As usual you pay what you want for a selection of games, beat the average price and you get some more, beat a predetermined price and you get even more than that.
The basic bundle consists of Bioshock, The Bureau: Xcom Declassified, and The Darkness II. Beat the average (currently at $7.33) and you also get Bioshock 2, Mafia II, and Spec Ops: The Line. Pay more than $20 and Xcom: Enemy Unknown and Bioshock Infinite will unlock. More games will be added as the campaign progresses.
With 13 days and 9 hours remaining there's already been 159,000 bundles sold and as usual you can decide what portion of your money goes to the publisher and what goes to charity (American Red Cross and Action Against Hunger).
Here's the link in case you missed it earlier in the text.