This toolkit is amazing. It solves two of the big problems with doing game development with ruby: providing a ruby-esque API framework for writing game code, and providing an efficient interpreter with low-level tie-ins for better hardware performance. 

There are even new tools (IDE-like) to facilitate, and a lot of really solid community support.  Check out the available licenses if you're on the fence! (As a long time, 10+ years, Ruby programmer, this is _AWESOME_)