Geocaching

"Geocaching is a hobby that combines hiking and treasure hunting with the latest advances in portable global positioning system devices. Cachers, as they like to be called, hide waterproof containers — caches— and mark their exact locations with GPS coordinates that are posted on the Internet. Other cachers get the coordinates, punch the numbers into hand-held GPS receivers and follow the digital directions to the hidden prizes." (http://www.latimes.com/features/lifestyle/cl-wk-cover16feb16,0,2520493.story?)