The Feral Radar offers a teaser for upcoming OS X and Linux ports they currently have in the works. Some of the items on their radar carry titles, but some are more nebulous than that. In that vague category is one listing in the "soon" ring that shows what looks like an image of Mars with both OS X and Linux logos. That's all there is to go by, but it has inspired speculation that the game being ported is id's new DOOM. Thanks Ant.