After Knoppix 3.6 was released few weaks ago, there are more Live-CD distro being released. One of them is Slax 4.1.4. SLAX - Live CD is a bootable CD containing a Linux operating system. It runs directly from CD-ROM without installing. The live CD described here is based on the Slackware Linux distribution and is downloadable from its website as an ISO image. All scripts and source code which can be used to build your own live CD are also available.
Here are some updates included in Slax 4.1.4 (from DistroWatch): added Linux kernel 2.4.28-pre2 with SATA (libsata) support compiled in; added KDE 3.3.0, K3B 0.11.14; added cheatcodes.txt to CD's root directory; added MPlayer 1.0-pre5, recompiled with many options; fixed GUI script to better handle X auto-configuration; the Czech version of SLAX is available at slax.cz. Some other languages for SLAX are available as modules.
Slackware is the oldest GNU/Linux distros available right now. It's latest version is 10.0. Slackware is considered as one of the paranoid distros by some people around the world like Debian, since they only include packages which they think is very (i mean VERY) stable, but i think that Debian is worse than Slackware. Their latest version is 3.0rc2 and they still consider to use old packages (although you can update with unstable or testing packages with apt-get, the best package manager in GNU/Linux's world).