IronPython and IronRuby are Microsoft’s versions of the Python and Ruby development languages, modified for the .NET environment. Officially, IronPython and IronRuby have been open source projects released under Microsoft Permissive Licenses, but few developers consider that license to be truly open source.
Now Microsoft is quietly shifting the languages and its Dynamic Language Runtime (DLR) to the Apache License. That may spur more developers to become involved with the projects, because they view Apache as a true open source license. It’s also considered a business-friendly license.