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.