A.Little.Wit
I subscribed to Harper's magazine two months ago and have yet to receieve my first issue – or, enough time has passed, my second. Who knows if I ever will; I'm dubious.
In one of their subsriber e-mails, they liked to a 1961 article† about writing your Congressman/etc. It was both well done and timeless – aside from names, it could likely be published today mostly unchanged. It included this little bit, which I thoroughly enjoyed:
"Dear Sir: Fellow on the radio says to write your Congressman so just thought I'd drop you a line. Yours truly."