Gentoo is yet another distribution of Linux with a fairly FreeBSD feel to it. i.e. you have a /usr/ports or in this case a /usr/portage tree and you compile the whole system up from source, so you can configure things exactly how you want them, rather than relying on the way a particular package maintainer thinks things should be configured. It is deffinatly not for the beginner Linux user though as you don't even really get an installer with the ISO, you are expected to do all the partitioning, formatting, and configuration by hand with the help of a tarball with just enough to boot the system in it. see www.gentoo.org for further information.
