Martin Krzywinski at the Genome Sciences Centre of the BC Cancer Agency, created software called Circos designed to help elucidate the interaction of genes, and has used it to create some truly beautiful graphs.
The software is pretty complex, and I have only figured out how to use his simple on-line version, which limits the number of inputs. But, even so, here is an image I created using Circos. The image represents the number of emails exchanged by the top 10 most connected participants with each other, from an active large email list.
