http://www.X.org/ — Home page of the X.Org Foundation, which produces the X11R7.1 release of the X Window System. The X11R7.1 release is bundled with Red Hat Enterprise Linux to control the necessary hardware and provide a GUI environment.

http://dri.sourceforge.net/ — Home page of the DRI (Direct Rendering Infrastructure) project. The DRI is the core hardware 3D acceleration component of X.

http://www.gnome.org/ — Home of the GNOME project.

http://www.kde.org/ — Home of the KDE desktop environment.