The roguelike Dwarf Fortress has been given a pixel make-over in the form of Stonesense, a third-party visualiser for the game which is currently in its third alpha release. Stonesense takes the original ASCII-based graphics and converts them into isometric visuals.
The open source mod is being developed by "Jonask" and "Solifuge" with graphics currently being created by members of the Dwarf Fortress community. Check out the official thread here.
Also, head over to TIGSource for more info, a screenshot and a video of Stonesense in action.