Video Game Graphics and Open Source Gaming

I've been getting more interested in video game graphics again, and found these helpful links to share here:

http://en.wikipedia.org/wiki/First_person_shooter_engine

http://en.wikipedia.org/wiki/QuArK

http://www.quakedev.com/

http://en.wikipedia.org/wiki/DarkPlaces

http://www.tenebrae2.com/

http://industri.sourceforge.net/

I'm so glad to see that there is GPL gaming code out there. Seems a bit legacy at this point, but I'm feeling optimistic about the future!

This open source FPS looks awesome!

http://alientrap.org/nexuiz/

And here is a list of open source video games.