I'm so excited to have finally found this old article from Science News! Thought I'd lost it. So I want to share it here with you for posterity.
In a nutshell, a particular type of entropic force called a "depletion" or "excluded volume force" causes mixtures of big and little spheres (on the order of 500 and 100 nanometers in diameter, respectively) in suspension in a container to spontaneously separate and self-assemble as crystals against the container walls.
The article seems to be emphasizing the utility of this phenomenon in assembling nanostructures for industry and pharmaceuticals, but I was immediately struck by the fact that a closed system could actually self-organize through nothing more than entropy. The importance of this in arguments with Creationists should be obvious (assuming they could even understand it).
Too bad the pdf doesn't include the illustration
It was very ... illustrative. Here is the caption:
Walls and big balls create zones (light blue) where room to roam is lost by some part of each small ball. For instance, a small ball's center is stopped a full radius (r) away, whereas points on its surface roam everywhere. To increase room to move, or entropy, small balls herd large ones into the corners and against the walls and each other. Where surfaces of large balls and walls touch, the restricted regions overlap (dark blue), freeing unfettered volume elsewhere.http://www.sciencenews.org/pages/pdfs/data/1998/154-07/15407-15.pdf