John Lam, whose RubyCLR bridge has been a fascinating and seemingly highly-successful project, is joining Microsoft. Details are vague, but he says he'll "be working in the CLR team" and "I'm not going to leave the Ruby community" but makes it pretty clear that he's looking to hand off the RubyCLR codebase to the community (hmmm...I have such copious spare time...).
I'll be trying to wheedle details out of him, but I still feel that Microsoft will not produce a Ruby but, something at least Java:C#::Ruby:X if not even a little bit more of a Ruby-VB hybrid. Timing-wise let's say that Microsoft has designed a "more dynamic" language (VB.Nexter, Sapphire [Perl->Ruby->Sapphire]). One could well imagine that they might be in a good position to develop a back-room prototype for PDC2007.