Water goes bouncy.

Another tutorial altering particles.

I made a box, and put a slightly smaller box in the middle of it, and gave it a "fluid" particle effect. I used the outside box as an "obstacle", and a much larger box around the entire scene as the "domain".

I tweaked some of the ray transparency values of the inner box and coloured it to make it look like water, and then "baked" the animation.

The final result was not bad, but the water looked slightly solidic, this could be improved by sub dividing the rectangle.