IPython

IPython is an improved Python shell than the one you get from running $ python in the command-line. It has many cool functions (running Unix commands from the Python shell, easy copy & paste, creating Matplotlib charts in-line etc.). You can find all functions in the documentation.
IPython is a kernel for Jupyter Notebook. If you are confused IPython with Jupyter, refer to the Jupyter documentation

Installation

$ pip install ipython

If you want a more fine grained command you can try the following:

For zsh -> $ pip install 'ipython[zmq,qtconsole,notebook,test]'

For bash -> $ pip install ipython[zmq,qtconsole,notebook,test]