You got me thinking with this thread...
Apparently, there is a geocache somewhere on the berm behind our house. I have no GPS, but there are only a few places it could be hidden... I might venture over there tonight and see what I can find!
Well your getting a new Iphone soon right? (unless I'm remembering wrong) That has a GPS on it and they even make an app for that! (geocaching)
We love letterboxing and geocaching! We tell our kids that we were selected to go on secret spy training missions, and that the boxes/stamps were put in place by other spy trainees or sometimes (if there is a really cool stamp or prize) the actual spys. (they are still young enough to buy it, and yes we are prepared for all the therapy we will have to pay for in the future!)
It's a great way to get the family outdoors!
My only advise is to not get discouraged if you find boxes are missing, and for this reason we try to stick with ones where there are more close by. That way if one is missing we can quickly move on to the other.
My kids think the best part is being sneaky and not letting the "muggles" know what we are doing, so they have the most fun with the ones in populated areas.
(we have a micro one attached to a metal beam in our local Ikea! That was fun!!!)
We especially love letterboxing because it doesn't require a gps, just gives clues to solve, and that makes it easier for the kids to be involved in the search.