Last year, my son took some time off university and spent six months in China – mainly in Beijing.  He had plans to do some English teaching while he was there even though he is not a trained English teacher.  I gave him a going away present – a book “Lessons in your rucksack: The complete TEFL guide” by John Hughes (pub Modern English Publishing 2005).  He had a rucksack and did use it for a number of lessons. 
I have just take up a teaching post in Hong Kong.  While I don’t have a rucksack, I now have a better understanding of some ways that TEFL and TESOL differ.  I have a lot to learn.  I brought the book with me just in case it might be useful – and it has been.  I have found it a rich source of ideas especially for conversation activities.  I also like the hints on what to do when there is not unlimited access to the photocopier as I have had in the past as well as ways to use local resources.  Highly recommended!