My school's science club that I sponsor does some geocaching. I use it coordination (no pun intended) with GPS/GIS and mapping with my 8th grade science studies. We also try to locate caches on our field trips when possible.
Personally, I'm an Earthcache fan. Having a geology background, I love to check out some of the more unique sites and see how they fit in the big picture.
-Troy

Get your facts straight bucko!
See you in the cave on Saturday. 
you are.