Recently, my mom came over to teach us some basics of calligraphy and it intrigued everyone. She brought guides and tracing paper for us to try to make decent looking letters. It was so much harder than I expected. The letters are not drawn in the typical sequence, so you are unable to write quickly - you have to pay attention to so many little motions, constantly correcting your hold and angle. I imagine it would be very relaxing and mediative if not done with three kids swirling around.
My kids love the story of Steve Jobs studying calligraphy and the lesson that you never know what interests will be useful later in life is a good one.
A jar of ink and a few pens are pretty reasonable and can offer even the most reluctant writer to explore penmanship in a fun way.
Even my 5 year old experimented and loved writing with the nibs. While, I do not think we have any passionate calligraphers among us, we really enjoyed learning about it and continue to use the supplies in writing letters, journalling and making treasure maps.
If you like this, you might also want to try writing with quills and making your own ink!