GPU based particles – How to render a million particles in real time

GPU skinning

Normal Mapping
Parallax Mapping
Displacement Mapping
GPU Mesh Instancing
Deferred Rendering
Non clipping particles – z-buffer technique for fading away as you get closer to the z buffer behind the particle
Radial Blur - for light shafts, and cheap full screen motion blur as seen in Burnout, and other driving games
Post Processing - films are using this more and more to create atmosphere
Texture Synthesis - How to tile non tiling textures