This is really neat! I learned about "letterboxing" from Emphasis on Moms, http://emphasisonmoms.com/, Founder Dionna Sanchez through her newsletter. Stop by her site and sign up for a copy. She is so inspirational!
 
Learn more about letterboxing here: http://www.letterboxing.org/
 
This is a great activity for the whole family! We are planning on giving this a try this weekend. There are actually a few letterboxes in my area.

In Friendship,