OpenMW is a free and open-source 3D role-playing-game (RPG) and game engine. The game is an open-source reimplementation of Elder Scrolls III: Morrowind.
"OpenMW is a new and modern engine based on the one that runs the 2002 open-world RPG Morrowind. The engine (OpenMW) will come with its own editor (OpenCS) which will allow the user to edit or create their own games."
Mac OS X 10.6 Snow Leopard or newer
OpenGL compliant graphics
Free download at sourceforge.net
Game website openmw.org