CG Animated Water
This video has been making its rounds around the Blogsphere lately, and for good reason. Apparently both the water and the sharks here are completely computer generated and that's quite impressive considering how realistic the water looks.
The water reacts naturally both above and below the surface, reacting to wind and things dropping into it with realistic splashes and bubbles. The mathematics behind calculating and modeling realistic water must be mind boggling. For once I'm glad someone else is doing this kind of stuff.
Link (via Drawn)