I don’t think many people are aware of it, but Gentoo Prefix is a valid alternative to MacPorts and Fink for installing unix-y type software on Mac OS X.
Personally, I just use it to install all those command line tools and utilities I miss from Linux.
Here’s my development-centric laundry list of things I’ve used it to install:
* version control
* cvs * darcs * git * Java stuff (yep, it supports Java using Apple’s SDK) * ant * maven * Others * nmap * keychain
So remember kiddies, Gentoo works on Mac OS X too!