Telerik, the company behind a number of popular developer tools for mobile platforms like Windows Phone, are making their suite of UI controls for Windows platforms completely free for the next four days in honor of TechEd 2014. This includes controls for both Windows Phone and Windows 8.
The company is also working on a new set of tools to support Microsoft's new Windows Universal apps. These allow you to, for instance, build a Windows 8 app that will also run on Windows Phone devices. Telerik's new universal UI controls will be available later this year. For those developers that claim a free license during the four-day free period, Telerik will upgrade that license to include the universal toolset when it's released.
You can claim your free Telerik controls license by going to the company's TechEd website.