Is there an easy way of doing "analytic ambient occulsion", like in this demo?

A lot of you have probably seen this. What I really like about it is the dynamic ambient occlusion, it creates a fake light bouncing effect that really give the scene a lot of realism. To see what I mean, move the ball closer to/further away from the walls and floor of the pool.

Is this simple to do in Unity?

http://www.chromeexperiments.com/detail/webgl-water-simulation/?f=webgl

 

If you have Unity Pro then yes, you could attach the SSAO component or create something similar using it as a base

Without Pro you won't get any dynamic fullscreen effect at all I fear