Aside from the official CPython distribution available from python.org, other distributions based on CPython include the following:
ChinesePython Project: Translation of Python's keywords, internal types and classes into Chinese. Eventually allows a programmer to write Python programs in Chinese.
Win9xPython: Backport of mainline CPython 2.6/2.7 to old versions of Windows 9x/NT.
Portable Python: Run Python from USB device - no installation needed.
PyPy: a Python implementation in Python.
PythonLabsPython: an old name for the python.org distribution
Tiny Python (archived link) - not to be confused with tinypy
EmbeddedPython for details of minimal or reduced size Python distributions and implementations.
The master list of Python implementations.
The following historical documents were previously used to describe Python distributions: