SGC Ruby CUDA has been heavily updated. It is now available from the standard Ruby Gems repository. Updates include:

• Basic CUDA Driver and Runtime API support on CUDA 4.0rc2 with unit tests.
• Object-Oriented API.
• Exception classes for CUDA errors.
• Support for Linux and Mac OSX platforms.
• Documented with YARD.

See http://blog.speedgocomputing.com/2011/04/first-release-of-sgc-ruby-cuda.html for more details.

SpeedGo Computing recently announced their development of CUDA bindings for Ruby. Currently, only part of the CUDA Driver API is included. More components such as the CUDA Runtime API will be added to make it as complete as possible. More details as well as sample code can be found in this blog post.