Audio Books are a great way to pass the time that is also very productive. Audible has most books, your local library may also have MP3 books you can rent for free, and librivox (booksshouldbefree.com) has many of the classic older (75+ years) for free. Listening to the books is easier than reading, if the bus is bumpy. You can spend the time looking out the window. The biggest problem is if you are on an Asian bus where they play the music videos too loud to hear...(trust me I have hundreds of hours of experience there....)