Ruby implemented on top of Mac OS X core technologies.
MacRuby is a version of Ruby 1.9 ported to run directly on top of Mac OS X core technologies such as the Objective-C common runtime and garbage collector, and the CoreFoundation framework. While still a work in progress, it is the goal of MacRuby to enable the creation of full-fledged Mac OS X applications which do not sacrifice performance in order to enjoy the benefits of using Ruby.
What's new in MacRuby
Release notes were unavailable when this listing was updated.