The Future of Ruby
From eqqon
Introduction
Yukihiro Matsumoto's C implementation of Ruby aka MRI (as time of this writing the stable version of the MRI is Ruby 1.8) is considered the Quasi-Standard of the Ruby Language because there has never been an explicit language standard for Ruby. As the number of implementations grows a formal standard seems to become necessary to prevent the horror szenario of multiple incompatible interpreters on different platforms.
There have been some attempts to summarize the language's features but none is complete neither completely up to date with the current MRI.