OpenMW is an attempt to reimplement the popular role playing game Morrowind. It aims to be a fully playable implementation of the game that will run on Linux, Windows, and Mac OS X. No game data is distributed with the code; the user must already own a copy of Morrowind to use the software.
openDarkEngine is a from-scratch rewrite of the famous Dark Engine originally written by Looking Glass Studios. The engine was used in the Thief 1, Thief Gold, Thief 2, and System Shock 2 games. This rewrite is targeted at newer machines and should improve compatibility and give the games (and all the fan made material) a never ending life. It should also allow manipulation of the original data files.