H2O/IP
AltImage writes "This interesting project uses water as an organic network between two computers. It analyzes the color of each pixel and 'prints' out pulses to the electronically controlled water valve - a different pulse pattern depending on the color of the pixel on screen."
There was another link I can't find anymore to a lab moving microscopic drops of water around on a sillicon substrate really fast. The target apps are in biochemistry, but iirc the design used the liquid to do some logic, also.
"A language that doesn't affect the way you think about programming, is not worth knowing" - Alan Perlis