Arch Linux's Arch User Repository (AUR) is a community supported repository for unofficial packages. For end users, it provides a wider array packages at the expense of package quality and requiring compilation. For AUR package maintainers, it provides a way to contribute to the Arch Linux community without the large time/energy devotion of a full contributor.
I manage my AUR (Arch User Repository) packages using a combination of Git submodules and a script that automatically checks Ruby Gems and PyPI packages for new versions.