When you buy your ticket for Jungfraujoch, I bet you are all excited about going right to the top of the top most peak in Switzerland. You have come all the way to Switzerland and to most people, like me, it is a dream trip and every moment of the travel is precious as you savor the beauty of the Swiss sights.
At the ticket counter, the clerk hands you a ticket, guide book and a train schedule sheet. The guide book is most often no read or even trashed sometimes. Few people carry it back home to read it after the trip. What I would do is glance it quickly and that it is how I came to the last page that is a precious personal souvenir of Switzerland, in itself. A thank you note from the the CEO of Jungfrau Bahn and space for you to stamp your date. When you enter or are about to leave for the train at Jungfrau station, there are stamping machines where you can push in your guide book and stamp it with the date and time. How cool is that?