This spring we shipped the first preview release of a new .NET library that we call the "Dynamic Language Runtime" (or DLR for short).  It provides a set of features on top of the CLR designed explicitly for dynamic language scenarios.  These include a shared dynamic type system, language hosting model, and support to make it possible to generate fast dynamic code.  These features make it much easier to build high-quality dynamic language implementations on .NET.  These implementations can access and use any of the APIs in the .NET Framework, as well as easily interoperate with code written in any other .NET language (for example: you could write a Ruby class that invokes and uses a C# class, which in turn invokes a Python class).

This spring at the MIX 07 conference we announced that Microsoft will be shipping 4 dynamic language implementations of our own for .NET:

·         IronPython

·         IronRuby (new)

·         Javascript

·         Dynamic VB (new)

The source code of our IronPython implementation, as well as the source code for the underlying DLR library, was published on CodePlex in April.  You can download both of them today from the IronPython codeplex site.  All of the source is made available under the MSPL permissive license - which provides full commercial and non-commercial modification rights.