I work on the Composition team at Microsoft that builds the Windows.UI.Composition APIs for the Universal Windows Platform.
This project is where I'll be putting demos of the API's functionality when I get time :-)
Our official team sample repo is here: https://github.com/Microsoft/WindowsCompositionSamples
Recently added some examples of Vector Graphics which you can read about in this blogpost
There are also some more C++ demos in my fork of Kenny's cppwinrt demo project here: https://github.com/clarkezone/cppwinrt