I've seen Les Stroud make distilled water by putting a plastic bag over a container with urine in it. It had a small collection cup in the center, and a small rock in the middle of the plastic so the water that collected on the bag would run down to the center and drip into the collection cup.
I wouldn't recommend it for daily use, but if you're about to die of dehydration in the desert, it could save your life.
Really, this method can be used on anything with water in it, branches, cactus, rainwater, stagnant water, even sea water. It works even faster if you have a heat source like the ability to put this contraption in the sun.
here's a pic:
