Creating XML using Ruby's Builder class

Ruby provides a very simple way to generate XML.  It works well, especially when dumping values from your models in a specific manner that doesn't align with how ActiveRecord generates xml.

• Provide a simple way to create XML markup and data structures.
http://builder.rubyforge.org/

• Incorporating namespace declarations into tags.
http://stackoverflow.com/questions/4764185/ruby-xml-builder-how-to-create-this-namespace

For reading in XML and inserting or updating nodes, you will need to use another library like Nokogiri.