I don't know with you guys, but i think the bus tickets that are neglectfully left in your jeans' pockets or in your purses after a backpacking trip from other countries can be a brilliant idea for a bookmark. I was in a city bus, heading to Likas Bay in Malaysia, staring on my bus ticket when i thought of the idea. Bus tickets, usually, are written by the national language of the country and it reflects the amount paid for the ride in that country's currency. It's a nice souvenir, right? How about you go a little further and laminate it? You preserve the ticket souvenir, at the same time you have created an interesting international bookmark.
Here are the tickets I've got from a recent trip, Malaysia and Brunei, and from last year's trip in Vietnam. I've placed two tickets in one row and laminated it. You may leave it as is or you may put a hole on one end and put some frills that match the color or theme of the ticket.