A chat room app. Used this project for experience with Bootstrap modals, promise callbacks, and working with the Firebase API.
Assuming you already have NodeJS and NPM installed, once you pull down this project and install dependencies you can run it with the basic npm start command and explore it.
It will require you to set a username when you begin, but security and authorizations weren't a focus of this project so no other password or steps are required to begin testing it out.