As any good game Geocaching needs an achievement system. It is a great motivator to go out in search of those special caches. Not just the plain traditional.
Time to move 50 Find all caches within a 12 miles radius of your home
Child of darkness 10 Find 10 Night caches
Box Set 10 Find a Geocache set of 5 or more caches
Sequels 10 Find a Geocache series of 4 or more caches
Thrillseeker 20 Find 10 caches marked with any "Hazards"
Challenge accepted! 10 Find a cache that "may require wading" without getting your feet wet
You feel the need! 25 Be the FTF 10 times
Im on a boat! 10 Find a cache that requires a boat