I just read about a cool project called the Reverse Geocache Puzzle. This man assembled a gift box which is locked from the inside and can't be opened until it is taken to a certain location.
Who knew what fun people would have with GPS...
Anyway, I stumbled upon this story through the writings of a man who plans to put a ring in his own puzzle box, and use it to propose to his girlfriend in a special location.
As it says in the follow up to the original story, "it’s the perfect combination of mystery, software, romance, and mechatronics."
Awwww. Nerds in love are the best.