The list author says: "If you haven't "geocached" before, you are missing out: Geocaching is basically a treasure hunt where you try to find a hidden box based on GPS coordinates. You don't need much to get started - really just any GPS unit that allows you to enter latitude and longitude coordinates; and, a free account on geocaching.com. I've found that there are some other items that make things easier."
"Almost any GPS unit will work, but I've found DeLorme's PN-series to be exceptional. The PN-60w isn't actually available at this time, but it is what I would pre-order if I didn't already have a PN-40."
"If you are going to swap items, you need something to swap -- if you are geocaching with kids then this is the most important part. I get some different things to keep in the pack, my latest addition was a 20 pack of Hot Wheels."
"I like to have some food in the pack. You can't swap it in the geocaches, but sometimes the kids get hungry. And sometimes, I am one of the kids. It is worth having something that can just always be in the pack until you need it."