I have always like the 1948 Franklin Half Dollar as the first of its kind. Here is an interesting challenge that will probably never be met. When the Franklin Half Dollar was introduced in 1948, there was a reception and dinner held at the Franklin Institute in Philadelphia on April 29, 1948. Each of the 200 guests who attended received a place card with a Franklin Half Dollar affixed to it with a short statement about the event. I have never seen nor heard of any of these place cards. I learned about this event from an article that was printed in an old book I have, Selections from The Numismatist, United States Coins. If you have the book, the article is on page 169.
I’ve heard the same thing but I’ve never seen one and I would buy one in half a heartbeat if I ever found one.