Google services such as Calendar, Analytics, and Google+ allow users to store personal information and manage their activities online. Most Google services have web APIs that you can use to give your applications access to this information with the user’s authorization. As Google mentioned in their blog, “Whether you are plugging Google Calendar into your .NET Framework-based application, translating text in a Windows Phone app or writing a PowerShell script to start Google Compute Engine instances, the Google APIs Client Library for .NET can save you tons of time.”
This library is an open-source effort, hosted at NuGet, that lets developers building on the Microsoft® .NET Framework to integrate their desktop or Windows Phone applications with Google’s services. It handles OAuth 2.0 integration, streaming uploads and downloads of media, and batching requests. For more than fifty Google APIs, it is the easiest way to get access for any Windows developer.
This is a surprising move from Google given the fact that they have largely ignored Windows platform for their Google services over the past few years. Check out the APIs here.