Beautiful writing was once a very important part of one's education. Now, it has become yet another item on the list of things that have been lost over the years. But, it doesn't have to be that way. Beautiful writing is an art as well as a practical skill and calligraphy often takes it to a whole new height. So here we have a lot of possibilities for teaching practical skills, art, one can link it to history, through illuminated manuscripts for instance and just plain good writing. In Charlotte Mason approach, dicatation and copywork figures very prominently to teach all kinds of subjects including science, math and geography besides other things. More on that later. But here is a link to a number of penmanship and calligraphy links from Meggiecat, a blog that is no longer updated regularly but has a ton of amazing crafty stuff in the archives.
Some even claim there is a whole science called graphology that explains how a person's handwriting reveals a lot about the author's character when one knows how to analyze it. A fascinating subject to explore in conjunction with psychology perhaps.