As you read about or discuss GPS, you may encounter the term geocaching.
Geocaching (see Wikipedia page on geocaching) is a hobby in which people hide a container (a 'cache'), post its lat-lon (e.g., see geocaching.com as a place to post coordinates), and then other people try to find it. Common containers are hide-a-keys, prescription bottles, small Tupperware bins, ammunition boxes, or even paint buckets. (My favorite find was a tennis ball that had a slit cut in the side.)
Using a GPS unit, you can navigate to within a few feet of where the container is hidden; once you're in the geocache zone (GZ ), you have to think like your opponent: If you were hiding something here, where would you hide it? Likely spots are in a hollow tree or stuck magnetically to the backside of a metal pole or fence. Part of the fun of geocaching is coming up with crazy ways to hide objects and thus challenge would-be finders. One ever-present possibility is that the cache has been lost, moved, or removed due to animal activity, erosion, or human error.
Once you have found a cache and opened it up, there is typically a log sheet inside to sign and sometimes objects to take or trade. This reinforces the social nature of the hobby–after all, if you are a hider, you may never see or meet your finders; if you are a finder, you may never see or meet your hiders.
We can see what geocaching has to do with geospatial tools; what does it have to do with teaching and learning?
In my opinion, geocaching is not a very suitable educational activity. (Others disagree, and that's fine.) Yes, geocaching can be fun and teachers should mention it to students, but I don't think it's a particularly good use of instructional time or resources. Using latitude and longitude to navigate to the GZ is great and educationally appropriate, but the uncovering stage is just an exercise in managed frustration–is the cache here? Over there? Under that? Hanging from a branch? Or maybe the cache has been lost or misplaced? I suppose it's no different than having students do a word search puzzle...in which there is a possibility that a word is missing from the puzzle. (I'll let you draw your own conclusions from that analogy.) Also, depending upon where the geocache is hidden, you may be exposed to poison ivy, mosquitoes, spiders, gnats, bees, thorns, brambles, mud, tar, etc., as you search for it. In my experience, very few students are big fans of any of these things, and parents and school administrators have even less tolerance for kids coming home looking like they've spent the school day bushwhacking.
I use a form of geocaching that I call a scaffolded geocache: The caches are all obvious (you know them when you see them, such as an orange cone or a yellow tennis ball or a colored chalk marking), they are located within a bounded area (e.g., on school property), and students work in pairs and use worksheets to help decompose the task. The only goal is navigating into the GZ; once you're in the correct GZ, you don't have to puzzle (much) over uncovering where things are hidden. By emphasizing navigation over uncovering, students receive maximum practice in the skill of using latitude and longitude, but zero practice in bushwhacking (which is not exactly a standards-aligned instructional activity).