You can never have too many vintage-style telegrams.
This is based on a mix of the RCA and Imperial "Radiogram" forms in use from the 20's to the 40's. Once you've downloaded the PDF from Google Documents you can customize the message text using the embedded form fields, then print, trim to size, fold, and insert in a coin or business envelope. For best results use a color printer, but everything is legible if you use a monochrome inkjet or laser printer.
This telegram prop was originally created for a group tackling Chaosium's epic "Masks of Nyarlathotep" campaign for the "Call of Cthulhu" role-playing game. The players are keeping a written record of the adventure in a leather-bound journal, an idea inspired by the "Grail Diary" from "Indiana Jones and the Last Crusade". I was asked to produce improved versions of the included handouts as well as supplemental materials like period maps and ephemera. By the time they finish the campaign the journal should be an impressive piece of work, crammed with all kinds of paper props.