RevitRubyShell on Github - installer
What is Ruby? Ruby is a dynamic, reflective, general-purpose object-oriented programming language that combines syntax inspired by Perl with Smalltalk-like features...Ruby supports multiple programming paradigms, including functional, object oriented, imperative and reflective.
Thanks to Håkon Clausen, Ruby is now friends with Revit.
Quote from The Building Coder:
Last week, I provided a short description of the interactive real-time Revit programming environment RevitRubyShell provided by Håkon Clausen and mentioned how impressed I was by its minimalistic single-click installer.
The Building Coder: RevitRubyShell Implementation and Installer