Over his storied (get it?) career as a children's book publisher, Klaus Flugge received hundreds of envelopes illustrated by authors. He's shared some of his favorites (like the one above) here.
As I perused these in wonder and delight, I found myself pondering why someone would spend so much time customizing something as disposable as an envelope. Were these letters particularly important? Did Klaus Flugge include a clause in his contracts that illustrators had to grace him with periodic free art? Then it occurred to me that there doesn't have to be a reason, the illustrators could have just felt like creating for the pure joy of art. Can you imagine the delight of the mail sorters and carriers? The secretaries? These envelopes must have passed through numerous hands before they reached Klaus and elicited all kinds of smiles. So, why not do the same when you send off a letter with your little ones. Even if they're not writing yet, have them decorate the envelopes. I'll bet the lucky recipients will treasure what was once mundane made beautiful!