An anonymous reader writes to this article about a series of visualizations built from London bike rental data
. "My favourite is the second map, it shows the main routes that exist between rental areas, coloured according to the local communities that exist in the network. So you can see the major flows of bike traffic within the city, which are mostly between major railway stations and work destinations. You can also see how the different local networks relate to each other — Hyde Park is its own little world, for example, while the networks around Kings Cross, Waterloo, and Liverpool Street are far more interconnected."
(Several more just-as-interesting maps here, too
. Wish every city had an interface to this kind of data, would make interesting reading for visitors as well as for locals.)