This included a Node.js server, a Ruby server, and a static version that works directly in the browser.

The Node version is probably the easiest to run if you already have Node.js installed. Run this command in the Terminal (from 0-start or 9-final):

    npm start
    
It will install dependencies and start the server on:

    http://localhost:9292
    
Otherwise, try the Ruby version:

    rake server
    
Or, try the static version. Drag 9-final-no-server/public/index.html to your browser.