Cartoonizer sample in C++ AMP
One of the case study samples in the C++ AMP book is called Cartoonizer and you can grab the code for it on the book's codeplex download page.
To understand the code, you can walk through the freely available aforementioned download on your own, or you can obtain the book and read the dedicated chapter to this case study.
If you need motivation for what it does, please watch this short screencast recording of the the Cartoonizer sample app in action.