Cython is a language that makes writing C extensions for the Python language as easy as Python itself. Cython is based on the well-known Pyrex, but supports more cutting edge functionality and optimizations.
If you read discussions about programming languages, one topic is quite common: "Why do people use an inferior language like Java/C++/what-the-hell and not a superior language like Lisp/Haskell/Python/you-name-it"?