X#
There is no such language called X# at Microsoft. There was an exterimental language developed that was data-centric, but it is gone and no longer developed and our team VS Data is responsible for helping get the good things from that research project into VB, C#, and the .NET Framework classes. You or someone should feel free to post my comments here on that Wiki page so those who read it in the future know that there is no such project at Microsoft and that the focus is on enhancing the VB and C# langauges for data as well as the .NET Framework classes.
Ken Levy
VS Data Product Manager
Microsoft
X# is dead, but if you want to know more about it, check this out. It is not really new (Oct 2002), but still an interesting introduction if you haven't seen it.