Interesting APIs. What would you use to study android?

Question

API

Actually I set myself a goal and a task: to write an android application using third-party APIs. As for example, a social network client for Vkontakte and so on. - but it's terribly boring and not interesting and useless.
Tell me some more or less popular services that provide an API that can be used in a boring training project (but any more fun than vk).
For example last fm etc.

Answer 1

Yes, any Google service. The same google drive, google map. You can not write a direct client, but somehow beautifully use this api to your advantage.