I just found a new .NET language List at Brian Ritchie's Dotnetpowered.com site and discovered a couple of .NET languages that are news to me. In particular, it looks like the ADA community is now on the boat with A#, a port of ADA to .NET, and Microsoft Research is at it again with Comega, an extension of C# that provides "A control flow extension for asynchronous wide-area concurrency (formerly known as Polyphonic C#)" and "A data type extension for XML and table manipulation (formerly known as Xen and as X#)." I have been wondering whether Xen/X# would eventually develop some traction. A# has been developed by the Department of Computer Science at the United States Air Force Academy and is "freely distributed" under the GPL.
Thanks to Brian for mentioning this Weblog as one of his "Other Sources!" I'm only too happy to have contributed something useful.