We caught up with this pilot after the hike and asked, "What is geocache?" His response was thrilling! Apparently there is a whole group of geocachers who roam the globe with GPS' telling them where hidden, communal treasures lie. Whatever, it doesn't make much sense when I explain it...but it's definitely worth watching this video:
There's also their website. This seems crazy fun, right? If anyone gets in on this and starts to geocache, will you let me know how it goes?