NodeJS, Express and Socket.io on Heroku
Socket.io is great
Socket.io allows you to run a Websocket server OR long polling server in the case of Heroku. This allows the connection between the server and the clients' browsers to be open and allow 2-way communication for very real/near-real time interaction.
To run locally
Install Node Modules
Start the server (assumes you have Heroku Toolbelt installed)
Visit in browser http://localhost:5000