Via Robot Wisdom come a page of travel-time maps. These are so intriguing that I was only mildy disappointed that they weren't "time-travel maps" as I'd first read it.
Essentially they are maps coloured by how long it takes to travel to somewhere from a fixed point. For instance the first map shows how long it takes to get from Cambridge Station to every other station in the UK, starting at seven o'clock on a weekday morning.
Useful to some, though not greatly surprising. More interesting is the comparison of car travel times to rail travel times starting from Cambridge, which, more than anything, shows how inaccessible some places are by train.
My favourite is the one based on tube travel times in London:
It makes London look like it being attacked by some sort of Whovian blobby mass, and who can resist that as an image?