PCLinuxOS, originally a fork of Mandrake/Mandriva Linux, was created by some guy known as "Texstar" from a set of RPM repositories for Mandrake 9.2 that he developed.
The default desktop environment is KDE, but these screenshots are of the "FullMonty" edition, which as you will see is quite unlike anything else I have ever looked at.

There really is no default desktop.
Rather the desktop is split up into six different sections, each with it's own specific genre of applications.

This kind of environment is a great beginner's environment because it keeps all the different programs separated into their own little environments, and makes running them easier as the user knows what kind of basic task the program is to perform.
However unlike BOB, Metro, Rooms, and other beginner GUIs, FullMonty is also great for regular and advanced users because the traditional K Menu is still there and you can do anything any other KDE-based GUI can do.