IronPython
IronPython is [http://hugunin.net/index.html JimHugunin's] implementation of Python on the .NET CLR.
You can download IronPython from http://ironpython.com/
Early results are promising, showing great performance, even better than CPython 2.3 on the Pystone benchmark, but remember this is an early prototype, not a full implementation.
These results caused a flurry of discussion, which has since died down, pending more information from Jim.
Other Python-Like Languages for .NET/Mono
Some other Python-like languages for .NET and Mono include:
[http://boo.codehaus.org/ boo] - Syntax is very similar to Python's, yet the language is statically compiled. It implements many features that have been suggested for ["Python3.0"], including a "with" statement and optional static typing, as well as closures and soon, optional case-insensitivity. See [http://boo.codehaus.org/Gotchas+for+Python+Users Gotchas for Python Users] for specific comparisons between boo and CPython.
[http://www.prothon.org/ Prothon] - now defunct
Accessing .NET from CPython
[http://www.zope.org/Members/Brian/PythonNet/index_html Python for .NET] is the reverse of IronPython, it lets you access .NET assemblies from CPython.
See also: PythonAndParrot