As part of the latest Humble Bundle, you can pay what you want for BioShock, The Bureau: XCOM Declassified and The Darkness II. If you pay more than the average ($7.48 as of this news article,) you also receive BioShock II, Mafia II, Spec Ops: The Line and more games that haven’t been announced yet. If you pay $20 though, you get all the aforementioned games, plus XCOM Enemy Unknown and BioShock Infinite.
It’s worth mentioning that people who purchase this bundle receive all the games on Steam with the exception of BioShock which has a DRM-free version. As usual, you can distribute the amount of money you pay for the games between the developer, Humble Store and charity.
The Humble 2K Bundle runs until July 22nd at 11am PST.
Source: Humble Bundle