Following the release of the .NET Framework v4 and Visual Studio 2010 Beta 2 earlier this week, the latest CTP (community technology preview) of both IronPython and IronRuby are available on CodePlex. This is the third build of IronRuby and IronPython running on the Dynamic Language Runtime that is built directly into .NET 4.0; these releases are built to run on the .NET Framework v4 Beta 2.
As before, this release allows you to use IronPython and IronRuby objects and types as .NET 4.0 dynamic objects from within C# and Visual Basic code.
These releases are roughly equivalent to the functionality found in IronRuby 0.9 and IronPython 2.6.