On Silicon Graphics machines, it is possible to boot from a CD in order to install operating systems. (This is how one installs IRIX for instance) Recently, images for such bootable CDs to install Gentoo have been made possible. These CDs are designed to work in the same way.
At the moment the Gentoo/MIPS Live CD will only work on the SGI Indy, Indigo 2 and O2 workstations equipped with R4000 and R5000-series CPUs, however other platforms may be possible in future.
The Live CD images can be found under the experimental/mips/livecd/ directory on a Gentoo mirror.
These CDs are highly experimental at this time. They may or may not work at this time. Please report success or failures either on Bugzilla, this forum thread or in the #gentoo-mips IRC channel.