We recently gave the book as a birthday present to a guy round the corner. He has two daughters of about 21 and 26 so perhaps has missed out on some of the things contained in the book!
I don't think there's an upper age limit for this book.
My friend bought one of these books for his grandfather and he is 75. He loves it and has already lost one of his shoes and tangled a kite in the telephone wires at the end of his street.