I haven't written a .Net-related entry for months, simply because I haven't had anything noteworthy to write. The last time I even opened up a F# code file was about as long ago. (But the "Active Patterns" are interesting.)
The DLR seems like a fascinating idea, though: a common runtime/implementation abstraction layer for dynamically-typed languages, similar to the CLR and JVM for statically-typed languages. Hmm, sounds familiar...oh, Parrot. Microsoft does seem to end up creating doppelgangers for everything, doesn't it? A monoculture just has to stay competitive, y'know.
Kidding aside, according to the linked blog post by Jim Hugunin (who has Jython and IronPython cred), the code is under a "BSD-style" license. I'm not great at legalese, so I can't comment on what the specific license precisely allows/enforces. If Microsoft keeps paying talented folks to produce good shtuff that doesn't lead to vendor lock-in, I find it hard to complain. Conflict is overrated. Yet the lack of specifications and fully-functional alternative implementations for important .Net pieces, like ASP.Net, gives me the willies.