The Evernote Java Sample Code by Evernote shows how to make several API calls by using Java. Normally, Evernote requires the use of OAuth authorization, but a developer Token can be used as well. This Sample Code demonstrates a way by which developers can integrate the Evernote API into their applications.
MyBantu is an interesting little mashup, available as an iPhone app, an Android app, and a website. Its goal is to make shopping for anything, especially restaurants and movies, easier and more social. It uses Yelp API, Netflix API and various others to make it happen. It's very similar in idea to Siri, the "ultimate mashup" that Apple later gobbled up in the largest mashup acquisition ever.
Have you noticed the many tools to share your location? There's FourSquare and Gowalla, both about a year old. Then there are old-timers like Brightkite. And now, there's one that works with all three (and a couple more).