Geocaching is a new outdoor sport which the whole family can get involved in, its great for exercise and it can be a very good bonding experience. People all around the world have put little treasure chests (a container of some sort) all around the world, some are in easy places to get and some are in rough terrain where the more experience geocachers will go for. All you need to do is get a GPS and get the coordinates off a geocaching website, one i can recommend is http://www.geocaching.com.
Normally the cache will be a waterproof container which contains a pen or a pencil in, a piece of paper or a book, which is used for logging how many times it has been opened and it should have a trinket of some sort. Trinkets are something like a key-ring or something small, remember if you do take something from the container, it is always nice to replace it with something else so the next person who tries to find it has something for them to get.
Types of Caches
Traditional Caches: A traditional cache normally contains a log book and a few trinkets in.
Multi-Cache: A multi-cache has co-ordinates inside of them, they lead from 1 to another until you reach the end.
Offset Cache: These are normally a 2 stage cache, the first box will then lead you to the next one which should be the final cache.
Night Cache: These normally can only be found at night, they follow reflectors or some sort of light source to the next one.
Mystery Cache: A mystery cache is one that contains a puzzle inside, some might lead to a false cache but that is all part of the puzzle. You must solve it to find the treasure.
Traveling Cache: This is more like a traditional cache but when it is found the box is then moved to a different location.