From a quick overview I really like your approach: you start by a hello world directly (then template, then models) instead of doing this strange approach of the django official tutorial that starts with model then admin interface then show an hello world at part 3. I also really like the presence of exercices.
Quick comment: here, you are teaching render_to_response http://www.tangowithdjango.com/book/chapters/templates_stati... while you should be using render instead https://docs.djangoproject.com/en/1.5/topics/http/shortcuts/... which is simplier than render_to_reponse (where you have to use the horrible context_instance=RequestContext(request) to be able to do certain things in the template which confuse a lot people).
Thanks for this contribution to the django community!