NVIDIA release two new technology demo's, showcased at the GeForce GTX 470 and 480 release.
The first one is Real-time Hair Rendering on the GPU. Simulating and rendering realistic hair with tens of thousands of strands is something that until recently was prohibitively expensive for real-time use.
The second demo is the Island Demo. This demo includes water with realistic and physically simulated waves.
Both demos (island and hair) are based on hardware tessellation. If you have a DX11 class NVIDIA graphics cards, go have a peek.