I'm a latecomer to the activity but I now have my caching kit down. Doesn't everyone have a custom rubber stamp? I'm now at 50 caches, not that epic compared to some, but I have ticked off 4 countries and it gives me a great excuse to head out, and it adds a further exploratory element to my adventures.
The origins of caching are fascinating too. The earliest form of this outdoor hobby is probably "letterboxing" which was said to have started in Devon, England in 1854. William Grossing wrote in his "Guide to Dartmoor" that James Perrott placed a bottle for visitors to leave their cards at Cranmere Pool on the northern moor. This evolved into a set of boxes placed around the moor where hikers left letters and postcards, the next people to come along would pick them up and put them in the post - hence "letterboxing". The boxes were so remote that often weeks or months went by before the letters were collected and mailed, this gave an air of excitement, anticipation and mystery to the whole venture.
The idea behind "letterboxing" is taken to a new level with Geocaching, it leads adventurers all over the world in search of hidden goodies. If you're not a cacher give it a try, it's fun, interesting and often takes you to places you wouldn't go. Get started here.