The console for the primary version of Python can usually be opened by typing py into your windows console or python on other platforms.

$ py
Python 3.4.3 (v3.4.3:9b73f1c3e601, Feb 24 2015, 22:44:40) [MSC v.1600 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>

If you have multiple versions, then by default their executables will be mapped to python2 or python3 respectively.

This of course depends on the Python executables being in your PATH.