One of my customers asked me how to make a Windows 8 Xaml FlipView control that automatically loops.  After figuring out a technique that worked (adding duplicate items to be beginning and end of the FlipView.ItemsSource list).  I wanted to make an elegant way of packaging the solution.  I decided to use a Custom Attached Property and posted a sample with the code for the property here:

http://code.msdn.microsoft.com/windowsapps/Looping-FlipView-Attached-ab57350d

This is one of the great things about Xaml – the X in Xaml is for “Extensible”.