Booting Knoppix from a USB memory stick:
rz-obrian.rz.uni-karlsruhe.de/knoppix-usb/
Linux on a business-card-size CD-R:
damnsmalllinux.org/
Linux on a floppy:
toms.net/rb/
I think I’ll make a USB distribution for myself. Plug in, boot up, and I can save my email, bookmarks, and all the rest onto the stick. (Yeah, I know, flash memory degrades after 100,000 or so writes. Oh well, nothing’s perfect, make backups!)