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

Knoppix linux is a rather different kind of distribution. It runs entirely off CD. Knoppix is an excellent distribution to show people about linux, it probes your hardware and boots up into X with mozilla, openoffice, gnome, KDE and almost everything else you can think of installed. It can mount FAT32 partitions so you can save your work, or, alternatively, it can back up your "home directory" to a floppy disk. It's also kept very up to date, being updated a couple of times a week.

If you're interested in learning what this Linux thing is all about, I suggest you get hold of a Knoppix CD from somewhere, either d/l'ing it or asking someone at your local LUG to get you a copy which they will usually do in exchange for a small donation being made to the LUG. Most people have a spare Knoppix CD around just so they can boot linux if they have to on any machine that can boot off a CDROM.