One of the appropriated caches in our treasure-hunt cache project is this one. (You will need to be logged in to the GeoCache website to access the co-ordinates, but registration is quick, free and painless, and I don’t think I’ve ever gotten any spam from them).
There are nine such caches, each one leading to the next, and each one containing a URL that both contains more information about the repurposed space that particular cache is in, as well as tells you where the next one is. In addition, on that site, you’ll find a portion of the URL for the final, ultimate, SUPER-SECRET tenth cache. You need to visit all nine caches to get the whole URL for the final cache.
One last thing: when writing out the URL for the cache’s site in each of the booklets, I made an error: the beginning of each URL starts http://theocaching/ettinburg.com/****.html — but that’s impossible. It’s theocaching.ettinburg.com — with a dot, not a slash. Sorry about that. Just keep that in mind and you’ll be fine.