The programmer of JPython/Jython (a Python implementation for the Java Virtual Machine) apparently is working on an implementation of Python for the .NET Common Language Runtime. And first benchmarks look very good, better than some other attempts that were made at ActiveState. It looks like in the foreseeable future Python code can be used both within Java applications and .NET applications, in addition to the native implementation that already exists. I find that very pleasant, because it allows me to use my currently favored programming language even in silly Windows projects that we'll be dealing with in the near future.
In the Java environment I'm already using Jython as a convenient alternative syntax when I have to work with any foreign libraries in Java - Jython is much more comfortable there (and the interactive environment is absolutely great when you need to experiment with foreign libraries, because the documentation isn't sufficient again!).