It's funny. The first Linux distribution I ever used, way back in '05 on a terrible P2 laptop with 128Mb of RAM, was DamnSmallLinux. It ran in RAM from what I can recall, at least off my USB drive (the disk iso dd'ed to it) with a floppy as the bootloader to hit the USB :)

Those were the days. I also remember getting Slax to boot from the HDD, which it was never designed to do. Nostalgia...