I was sure that finding a version of this tale would be easy, and chances are good that in my search for it I focused on details that may actually have prevented me from finding it. Be that as it may, I found a Hebrew version, probably paraphrased by whoever posted it to a discussion forum, which I then translated and edited, and can include here.
Reb Zalman of Chelm wanted to invite Reb Kalman who now lived in another town to his son’s Bar Mitzvah. He went to the Chelm post office and started to dictate a telegram:Victor Hugo and his editor may have been experts at brevity, but it seems that the Wise Men of Chelm could beat them hands down.
"To the honorable Reb Kalman. I am honored to be able to invite you to my son’s Bar Mitzvah celebration on Monday, the 29th of Tevet, 5638 when the tefillin laying ceremony will take place.
Respectfully yours, Reb Zalman of Chelm."
As he was dictating the telegram he noticed the sign on the wall that listed the rate per word for telegrams and thought to himself that his invitation would be quite expensive to send. So he reviewed the telegram and tried to shorten it.
"There’s no need to write who the telegram is for, since everyone knows that I’d invite Reb Kalman to my son’s Bar Mitzvah ... and there’s really no need for the introduction or polite formalities. And since Reb Kalman circumcised my son he certainly knows the date of his Bar Mitzvah, so I don’t have to include the date. And ... and ..."
It was in this manner that Reb Zalman sent an empty, but free, telegram to Reb Kalman.