Ancestry has a nice new help page about DNA inheritance which uses the family names analogy to demonstrate recombination that was in the RootsTech session by Crista Cowan. This can be used to describe to newbies why testing many people in a family can be useful.
https://www.ancestry.com/cs/dna-inheritance
This is a little bit “advertisy” but scroll down to watch the letters change. This will useful for me to explain to my sister why I want to test her! 🙂
Monterey County Genealogy Society 
That is really excellent!