We met with our outdoor playgroup today at a local science center.  They have a new "quest" trail that is similar to something like letterboxing, but you find clues along the way to make a message.  Well, the kids just wanted to explore, so we nixed that, but after exploring one of the larger trails we went to a smaller "storybook" trail where you follow signs that have laminated pages of a book on it to read the book.  The book they have up now is one that is about animals leaving traces of things in the snow and you have to figure out what animal it is.  Had a great time with everyone!