The GameJolt Python SDK by Vinícius Castanheira communicates with the API to access video game functionalities such as data and trophies. It is a free project that includes documentation and can be distributed and manipulated according to GNU Public License.
Google's Cloud Video Intelligence API makes it possible to scan and search videos for nearly anything thanks to machine learning. Google says the tool relies on a simple REST API that can peek at every single frame in videos hosted in Google Cloud Storage. It may alter content discovery in video.
If you want to see in realtime what's going on Digg you can use their digg spy page. This popular Digg feature uses a dynamic Ajax UI to let you see diggs as they happen. And now it serves as a model for a growing number of mashups that use web APIs to give you a realtime window into activity on a variety of services.