You put stuff in a tupperware box, hide is somewhere and go onto the geocache site to register it. Like minded people then go look for the cache and write in a book that is usually inside the box then you go online to register that you found it. A treasure hunt really, You can get free travel id tags and attach to an item of your choice called a travelbug, these can then be moved around for others to find. We picked up a green crocodile from a short distance from here and took it to Sydney Australia and took a picture of him with the Opera house in the background, I hope the owner of the bug was ok with that.