1st small boy: "My dad's a numismatist"
2nd small boy: "What does that mean?"
1st small boy: "He collects money"
2nd small boy: "Where I come from, we call them beggars"

I can't remember the source of the quote. Somebody told me the joke at a coin club meeting a while back, but I can't remember who it was. I doubt that it was original.

My own personal numismatic quote, as seen on my website (www.VDBCoins.com), is original to me: “Life is too short to buy ugly coins.”

Hardly undying prose, but it has an Anglo-Saxon pithiness I like.