As announced today on Scott Guthrie's blog Microsoft has released a pre-alpha for IronRuby. IronRuby is Microsoft's implementation of the Ruby language which is a follow up dynamic language to IronPython. IronRuby is fully integrated with the .NET Framework and will be able to run cross-platform through Silverlight 1.1 as well as run on Windows desktop and server platforms through all versions of the .NET Framework. Users will be able to use the full .NET FX APIs from Ruby. IronRuby will be a community driven, shared-source project similar to IronPython. Microsoft believes IronPython project has shown that the community takes a deep interest to make languages work cross-platform and we also hope to do this as well with the Ruby community.
There are some great getting started samples that you can play with on Scott Guthrie's blog. Now to make it really simple for you to try out a dynamic language here's the first steps to getting going.
Running up RBX that you've just compiled and having it execute simple ruby commands through to WPF windows is cool.