I had luck sending http://www.friendda.org/ for intro talks. Not even signed, just the URL and "can we both agree on this?" in an email.
While I could easily see this working with friends, it not really what I'm looking for.
Here's so far here's the best expression of why I don't sign NDAs:
https://spin.atomicobject.com/2014/09/08/nda-stifle-creativi...