[MrScruff]

This isn't prerendered - it's real time. Prerendered water (as seen in movies) looks far more realistic than this. Check out the Naiad link someone posted above.

This is great for real time though. It's using a form of SPH which is far easier to adapt for GPUs, and can crunch through those particle-particle interactions.

High end offline water sims would use a different algorithm (usually FLIP), maybe run for several days to sim a few seconds and occupy 10's of Gb of memory.

If anyone's interested, download a copy of Houdini Apprentice for free and have a play.