Portable Linux Distros

I've always liked the concept of having an OS on a CD or lately a thumb drive. Something that I could carry around with me, plug in and reboot and I have an isolated system.

I've used Knoppix before (especially fun leaving it in someones drive so when they boot up the next day they are in Linux :) ), but I just saw this article at Lifehacker covering portable Linux thumb drive distributions.

Might have to give this a try, especially if it will work on my MacBook :)