After seeing my last post, Michael Gorven pointed me to a couple of articles discussing RubyGem and Debian's policy. I did a bit of googling after reading those articles and some others around Ruby and package management systems, and found an article on using easy_install with Debian.
Perl has CPAN, Ubuntu and Debian have apt/debs, Gentoo has portage. These are all various distribution or packaging systems, which allow you to download and install packages from the various systems fairly easily. Of course Python also has it's own system.