In case you haven't visited the main geocaching.com page recently, you may have missed the new, "What Is Geocaching" video. This is great. Normally, whenever I try to explain my obsession, err, I mean hobby, to my friends or family, I inevitably end up getting confused, blank stares in return for my trouble. Now all I have to do is point them to this video:
This explains it in terms that even my great Uncle Mortimer can understand.