In this day and age, sitting still for an 18 minute TED talk is not always easy, but Roman Mars' discussion of flags and design principles (extensible into design principles of most everything) is breezy and entertaining and worth a listen (and watch).
It also got me to look up my own city's flag — which, if it has one (we're sort of a low-profile city) is probably based on its seal / logo — https://en.wikipedia.org/wiki/File:Centennial_city_seal.png — which is not bad but is also recent enough to incorporate (amateurishly) some of the design elements Mars talks about (it also just got slightly tweaked and updated — http://goo.gl/GUOXKa).
Does your city have a flag? For that matter, does your state flag adhere to these design principles? And is that really important? (I think a good case is made here that it is.)
I LOVE talks like this! Thank you!
I think Sheldon Cooper did it better.