The Weasley Clock Project
John McKerrell of Blog What I Made has created an awesome 'Weasley Clock' using an old clock, some Arduino boards and location data from mapme.at.
In the Harry Potter books by J.K. Rowling, the Weasley family have a clock which, instead of telling the time, shows the location of each of member of the family. Instead of the hands pointing to the hours and minutes of the day they point to locations such as, 'Home', 'Travelling', 'School', 'Holidays' and 'Mortal Peril'.
John's clock grabs his location from mapme.at and shows his location at 'Home', 'Work', 'Pub' or 'Travelling'. If you want to create your own Weasley Clock a good place to start would be the mapme.at API.
Via: Blog What I Made