A form of treasure hunting with help from the internet and a hand held GlobalPositioningSystem device.

http://www.geocaching.com

The art of geo caching is simply to store a stockpile (a cache) at a specific location (the geo bit ;)
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There is also a movement towards virtual "geo caching" whereby information about a particular location is referenced on web pages (searchable by location, date etc and potentially directly linked to a GPS chip on an internet phone or PDA (PersonalDigitalAssistant). Example (sort of) is http://www.travelblog.org. Also some organizations have IVR (InteractiveVoiceResponse) based systems where you can dial a number from a phone, put in a code and get historical or other information on a location. Example is http://murmurtoronto.com. Immediate, personal and often more detailed than travel guides or brochures.