This site hosts the "traditional" implementation of Python (nicknamed CPython). A number of alternative implementations are available as well, namely

• IronPython (Python running on .NET)
• Jython (Python running on the Java Virtual Machine)
• PyPy (A fast python implementation with a JIT compiler)
• Stackless Python (Branch of CPython supporting microthreads)

Other parties have re-packaged CPython. These re-packagings often include more libraries or are specialized for a particular application:

• ActiveState ActivePython (commercial and community versions, including scientific computing modules)
• pythonxy (Scientific-oriented Python Distribution based on Qt and Spyder)
• winpython (WinPython is a portable scientific Python distribution for Windows)
• Conceptive Python SDK (targets business, desktop and database applications)
• Enthought Canopy (a commercial distribution for scientific computing)
• Portable Python (Python and add-on packages configured to run off a portable device)
• PyIMSL Studio (a commercial distribution for numerical analysis – free for non-commercial use)
• Anaconda Python (a full Python distribution for data management, analysis and visualization of large data sets)
• eGenix PyRun (a portable Python runtime, complete with stdlib, frozen into a single executable file)