This precinct reports 43.7 gallons for Clinton, 31.9 for Dole. Thing is, you're limited in how many different issues you can vote on that way. Cast too big a vote for President and you'll have nothing left for your Congressman. But that may be an advantage, because you get to apportion your vote by strength of feelings. There have been voting systems sort of like that, but none using urine as far as I know.
More questions arise.
And under this system women would find voting more awkward than men would. This clearly needs work before it will be practical. It consists of a grid of spaces on which individual cells live or die according to certain rules. It was invented by John Horton Conway and popularized by Martin Gardner who wrote a number of columns about it in Scientific American. The only requirement over and above standard Windows is a mouse.