You can see it in action, right here: http://app.dave.ly/flags/
I've been playing around with Angular JS this weekend and built this simple web app using AngularJS and Node to quiz users on random flags of the world. Work in progress.
Note: This doesn't have all the flags in the world, yet. But hey, maybe you'll learn something while you play with it! :)
To use:
npm install
bower install