Nokogiri - HTML, XML, SAX, and Reader parser with XPath and CSS selector support

Nokogiri (?) is an HTML, XML, SAX, DOM parser. Among Nokogiri's many features is the ability to search documents via XPath or CSS3 selectors, XML/HTML builder, XSLT transformer. Nokogiri parses and searches XML/HTML using native libraries (either C or Java, depending on your Ruby), which means it's fast and standards-compliant.