You need to get in quick for this offer. I only found out about it today and it expires tomorrow (20th September). You can get a free copy of 'Invent to Learn: Making, Tinkering and Engineering in the classroom. This book has been described as the bible of the makers movement in schools.
I haven't read it yet but I intend to. don't be fooled by the title. It is not just for teachers of STEM subjects. The development of new technologies has turned us all into makers.
Download it free through this link. The paperback copy is normally $28!