The Doom 3 Engine is now open source and readily available for all those that want to make their own games using this great 3d engine. Or to even simply mod and improve more on the original Doom 3 as now the full tools are available.
I really think its great that developers care enough about the community and gamers in general to offer up these tools for free and to allow others a chance to make their own worlds and dreams come alive. There are alot of creative and intelligent people in this world that are just looking for another platform to paint on.
You can find the source code and files below from Github. Which is very similar to Sourceforge which hosts open source or GNU type programs to the public.
You can pick up the source code here. Enjoy!