xoxo

https://github.com/rubyworks/xoxo

XOXO is a Ruby XOXO parser and generator. It provides a Ruby API similar to Marshal and YAML (though more specific) to load and dump XOXO[http://microformats.org/wiki/xoxo], a simple, open outline format written in standard XHTML and suitable for embedding in (X)HTML, Atom, RSS, and arbitrary XML.