WPF - Radial/Pie ContextMenu

WPF - Radial/Pie ContextMenu

I want to replace the default ContextMenu with a radial/pie ContextMenu
with custom MenuItems for my Multitouch WPF application. Therefore I am
trying to learn how to create a ContextMenu in the shape of a
circle/ellipse/ring etc and how to include the MenuItems along the
circumference of these structures.
While I found a few examples on the internet with which I can achieve some
results but have not found a simple, clean and good looking example yet.
Would be great if someone can give me a small example (or a reference to
an example) in this direction. Thank you!