HotCocoa::Graphics is a subset of the MacRuby project, which is being developed by Apple and other contributors, and is still in a pre-release stage.  However, you can download the latest version and get started with the power of HCG – just follow the download instructions at Rich Kilmer’s MacRuby site.  Eventually HotCocoa::Graphics and MacRuby will be included in a default Mac OS X installation.

HotCocoa::Graphics was written by James Reynolds, with contributions from Rich Kilmer and others.