Cython is described as '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' and is an app in the Development category. There are three alternatives to Cython for Linux, Mac and Windows. The best alternative is Numba, which is both free and Open Source. Other great apps like Cython are Shed Skin (Free, Open Source) and Berp (Free).
Shed Skin is an experimental compiler, that can translate pure, but implicitly statically typed Python (2.4-2.6) programs into optimized C++. It can generate stand-alone programs or extension modules that can be imported and used in larger Python programs.
Berp is an implementation of Python 3. At its heart is a translator, which takes Python code as input and generates Haskell code as output. The Haskell code is fed into a Haskell compiler (GHC) for compilation to machine code or interpretation as byte code.