Pupu is a framework-agnostic plugin system for media stuff like JS/CSS frameworks and its plugins, icon sets etc. You can search GitHub for more examples. It provides CLI interface for searching, installing and updating pupus from GitHub and it also provides a helper for including static files from pupu into your HTML page. Both CLI and helper can handle dependencies.
CLI example:
pupu install botanicus/autocompleter ~ Downloading botanicus/autocompleter ~ Downloading dependency botanicus/mootools
MooTools is great JavaScript framework
# for basic functionality pupu :mootools # for mootools-more pupu :mootools, :more => true