Nvidia just announced today that it will bundle upcoming post-apocalyptic horror game Metro: Last Light with the purchase of any GTX660 or higher graphics card (basically most of their GPU models). The promotion starts today and looks like a North American and European affair (sorry, South America, Australia and Asia!). Two months ago, AMD did the same thing with 3 then-upcoming titles: Crysis 3, BioShock Infinite and Tomb Raider.
Metro: Last Light is set to debut in America on May 14 and Europe on May 17. You can get the download code for the PC version of Metro: Last Light with any purchase of Nvidia GeForce GTX660 and above models. This includes the famous high-performance GTX680 all the way up to the newly released flagship GTX Titan graphics cards.