This video is an overview of all the 2013 Graphics Samples that are available for download
Programmable Blending Graphics Sample shows how using pixel synchronization with programmable blending you can reduce artifacts.
Adaptive Volumetric Shadow Mapping Graphics Sample allows you to efficiently render complex effects like smoke that accurately receive self-shadows and correctly cast shadows.
Outdoor Light Scattering Graphics Sample shows a high end visual effect that showcases how the scene responds to the light in a way that is convincing, and realistic.
This demo of the Adaptive Order Independent Transparency Graphics Sample show how you can sort objects to render in the correct order.