The games currently part of the Humble Jumbo Bundle include Natural Selection 2, Sanctum 2, Magicka + DLC, Orcs Must Die! 2: Complete Pack, Garry's Mod, and Serious Sam 3: BFE. The Humble folks claim buying these titles when not part of the bundle would set you back about $165, but for the next two weeks you can pay-what-you-want.
Sadly, only Serious Sam 3: BFE, Natural Selection 2, and Garry's Mod are Linux-compatible titles at the moment. More details on this game offering can be found via HumbleBundle.com and the trailer video below.