Maybe it's just me, but I'm more intrigued if a geocache hunt makes you think or entertains you more than just finding a specific coordinate and you're done.
For example, in the Kansas City area geocachers Steve & Mary Brown took a Monopoly spin on geocaching. There are 27 caches to find each representing a deed on the Monopoly board. Even the cache location has a nearby reference to a Monopoly space (i.e. street signs). Once you find all 27 title deeds, you're then given coordinates to a GRAND final cache.
Things like this make geocaching more of a game and more entertaining.
What are some puzzles or games you've seen with geocaching that you've had the most fun with?