Mashing up the London Underground
It's marginally more fun than watching paint dry, or receiving SMS messages telling you all the trains on your tube line are knackered for the rest of the day, and it's the result of some clever shits mashing up live departure data from the Transport for London API, with Google Maps:
The result? All the yellow pins represent the near-live locations of tube trains on the underground. Of course the same API data is available in a far more convenient form for commuters, specifically for smartphone apps - but this is far prettier to look at. You can stare aimlessly at the mashup for yourself here.