libxml-ruby doesn’t work on Windows (surprise, surprise!). One of our teams discovered that the version of Ruby on Windows has a XML::Parser class, but it is NOT libxml-ruby even if you try to install the gem. A workaround is to rename or delete the libxml.so file, and then you can use the real XML::Parser.
A few Pivots just whipped up a pivotal-apdex gem that allows you to calculate your application’s Apdex performance index via a simple command line tool by parsing Nginx or Apache server logs. Apdex is an emerging standard in measuring application performance. We were inspired by Lew Cirne, CEO of New Relic, who gave a talk about Apdex a few weeks ago at Pivotal’s office.