Basically, KNOPPIX is bootable cd with Debian, KDE, and TONS of other crap. It boots up, autodetects hardware, and loads up KDE. All without using a hard drive. Perfect for newbs wanting to check out Linux without breaking their Windows install.

http://www.knopper.net/knoppix/index-en.html

Now what's really cool, is that it can also be used as an automated Linux install tool.

http://www.freenet.org.nz/misc/knoppix-install.html

This install is simple enough, that total beginers should be able to do it without incident.

I just used Partition Magic / Boot Magic on my machine, ran through the KNOPPIX install, and now I've got a dual boot XP / Linux machine. It took a little time to adjust the partitions and such, but other then that, it was a painless install. And everything worked without incident. =)

"Cool Linux" is the same thing only using Redhat 7.3. Worked flawlessly on every pc i've run it on. Also allows you to save your configuration back onto a multisessioned CDR/W so you don't have to go through autodetection for a pc you'd be running it on constantly.
http://freshmeat.net/projects/coollinuxcd/?topic_id=924%2C122%2C91%2C75%2C925