You will need to install IPython if you don't already have it. I recommend the Anaconda distribution.
Make sure you have the latest packages. Follow the instructions.
Next download the contents of this repository
https://github.com/mlunacek/meetup_d3_2014/archive/master.zip
and unzip this in a location where you'd like to work.
Navigate to this location using your terminal (or CMD prompt for Windows) and type:
ipython notebook --pylab=inline
You should be able to run the notebooks.