"Puppy Linux is a popular Linux distribution that runs on less than 128MB of Ram.

We reviewed the June 2009 release v.4.2 of Puppy Linux, which comes in a 110 MB file download from their website, or from accepted mirrors. The iso file is then burnt to CD and runs as a Live CD. After installing the Live CD into RAM, I experienced my HP Laptop (2GB RAM) run faster than I’ve ever seen with any other OS or Linux Distro."