Distcc is a distributed C/C++ compiler. You can easily use a bunch of machines’ power to compile stuff. The setup isn’t bad at all. It’s just a non-root network service.
Gentoo.org has some nice instructions on setting up distcc for builds. Here, we have 2x Pentium 3 machines and 1x dual xeon helping me build nethack. Don’t have numbers on how much faster it was but it seemed faster. Most makes/compiles are annoyingly slow, this seemed ok.