Geocaching is a large-scale treasure hunt for which one uses small GPS handhelds to locate containers hidden in various mapped locations. In these containers are small items to be exchanged for other items or riddles to be solved -- anything to prove a geocacher has actually been where he says he's been (and found what he says he's found). Geocaching has been adopted as a social activity typically connected with traveling and environmentalism (as it encourages interacting and exploring oftentimes-natural locations).
If a biologist finds a rare sample of a fungus and knows this location only by its latitude and longitude, he can allow other biologists to find this same location and pinpoint it to a specific place on the earth. That discovery of the home of this fungus will allow scientists of various fields to study its region of proliferation/existence, and they can use GPS to navigate its home territory / where it is found using accurate measurements.