Sidux, a relatively new desktop Linux distribution, is based on Sid, the unstable developmental branch of Debian. The developers strive for an easy-to-install and easy-to-use modern Debian derivative, and pride themselves on remaining true to the principles and values of the Debian project.
Read it here
Sidux comes as a live CD in a few different configurations. I chose the 2GB DVD with a full KDE desktop for both i686 or AMD64 architectures, but you can also choose from a KDE-Lite or XFCE desktop version for either architecture; each uses less than 500MB. The download page warns that it's very important to burn the ISO onto a high-quality medium with disk-at-once, but I didn't see that until I was already running tests on the system; despite the warning, I didn't do anything different from usual and suffered no ill effects.