Nokogiri (鋸) is an HTML, XML, SAX, and Reader parser. Among Nokogiri's many features is the ability to search documents via XPath or CSS3 selectors.
a swift, liberal HTML parser with a fantastic library
The Libxml-Ruby project provides Ruby language bindings for the GNOME Libxml2 XML toolkit. It is free software, released under the MIT License. Libxml-ruby's primary advantage over REXML is performance - if speed is your need, these are good libraries to consider, as demonstrated by the informal benchmark below.
scrAPI is an HTML scraping toolkit for Ruby. It uses CSS selectors to write easy, maintainable scraping rules to select, extract and store data from HTML content.
Extract useful data from HTML and XML with ease!
scRUBYt! is an easy to learn and use, yet powerful and effective web scraping framework. It's most interesting part is a Web-scraping DSL built on HPricot and WWW::Mechanize, which allows to navigate to the page of interest, then extract and query data records with a few lines of code. It is hard to describe scRUBYt! in a few sentences - you have to see it for yourself!
A new short XML Parsing Algorithm implemented directly in less-than-500 lines. An easy-to-use XML Parser without any Native Dependencies. Its under continuous improvement as being used/tested under my other xml-parsing required projects. [What, Why, HowTo]: http://justfewtuts.blogspot.in/2012/03/xml-motor-what-it-is-how-why-should-you.html