Geocaching is an outdoor sporting activity in which the participants use a Global Positioning System (GPS) receiver or mobile device and other navigational techniques to hide and seek containers, called "geocaches" or "caches", anywhere in the world.
A typical cache is a small waterproof container containing a logbook where the geocacher enters the date they found it and signs it with their established code name. Larger containers such as plastic storage containers (tupperware or similar) or ammunition boxes can also contain items for trading, usually toys or trinkets of little value. Geocaching is often described as a "game of high-tech hide and seek", sharing many aspects with benchmarking, trigpointing, orienteering, treasure-hunting, letterboxing, and waymarking.
A Travel Bug is a dog tag used in Geocaching. It is moved from cache to cache, with a unique tracking number allowing its movements to be tracked online. Some tags are fastened to an object, known as a hitchhiker, before they are released into a cache.