Gentoo Linux is a Linux distribution built almost entirely from source. It has an advanced package management system called Portage. Some consider Gentoo a meta-distribution because of the incredibly flexible installation process.
One of the goals for Gentoo Linux 1.4 is the addition of the GRP--the Gentoo Reference Platform--which will allow users to install precompiled packages built to certain baselines specifications. This may be an attempt to appease naysayers; some believe that Gentoo users spend too much time compiling and recompiling common packages.
It is also possible to create tarballs of packages for distribution to other machines; this is particularly useful in the case of a homogenous computer setting, where one machine can build new or updated packages and the resulting precompiled tarballs can be installed on the rest of the machines without needing any further modification or rebuilding.