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.