AES is a (the first real) encryption open standard and although it is quite well known (if not famous) and widely used, it most certainly deserves to be better known to the wider public.
Jeff Moser has tackled just that by explaining AES in a short(ish) stick-figure comic strip on his blog.
It is nicely structured into four chapters, each adding a layer of complexity, but each one is a nice rounded explanation on its own. This way the reader can decide what level of technicality is enough for him/her and safely skip the rest.
These levels span from complete basics on encryption all the way to the mathematical formulas themselves, so there is absolutely no excuse for anyone not to read it.