Its getting downright exciting in the dynamic languages arena!
As a bonus, Microsoft is releasing all of this under a BSD-style license, the Microsoft Permissive License. Hopefully, this is a true BSD-style license without any gotchas, but if anyone knows more about the details of this license, please post a comment. On top of all this, Microsoft’s new cross-browser Silverlight plugin will allow all of this to run client-side in the browser!
Jon Udell has a podcast where he interviews John Lam about the DLR and IronRuby. John is the creator of RubyCLR, who was later hired by Microsoft to create IronRuby.