On this page you can test if a URL has cors enabled. Maybe we can put together a list of domains, that have cors enabled. When there is some interesting content, it will be possible to build some cool apps around them.
To enable CORS on once web service, is a great way to make data available. When it is enabled, it can enable new ways of collaboration. An API is provided, And creative frontend engineers get enabled to find new ways for presentation of that data.
Also for students it is infinitely more effective to implement apps backed with some real data.