Duke Nukem Forever

This game is and has been (if you haven't been following gaming news throughout the many eras and epochs that this game has been in the works) the perpetually-anticipated fourth in the series. The game's development saga is legendary, including a switch from the Quake engine to the Unreal engine and a string of unofficial release dates that stretch from 1998 to 20006 and beyond. Technically, developer 3D Realms has always promised the release of Duke Nukem Forever, "When it's done." As of this writing, the game is not yet done, but it is still in the works, and the promise is that, one of these days, you or your offspring will enjoy the fruits of almost a decade of hard labor for 3D Realms.

Rumors of this game becoming a multi-platform production have always been part of the epic journey that Duke Nukem Forever has taken over its development, and now rumors point to an Xbox 360 release. But until you hear from the Duke, don't assume anything about DNF, because when you assume, you're just an ass.