You can now access the Office 365 REST APIs from .NET and JavaScript, using a new set of client libraries. These libraries make it a lot easier to interact with the Office 365 APIs, from popular device and desktop platforms. The libraries are included in the latest update for Office 365 API Tools for Visual Studio Preview. Along with the libraries, this release also brings you some key updates to the tooling experience making it easier to interact with Office 365 services. 

Read all about it here! .NET and JavaScript Libraries for Office 365 APIs, Available in Preview

Download the tools here.

And for more developer-related announcements from TechEd, see Soma's post.