The Morris Dance …
… is traditionally danced on May 1st, to welcome in the summer. Its history is a bit confused, possibly because it’s often danced near pubs, but it is now the English folk dance. The dancers usually wear white, and have bells sewn on their clothes.
I invented the Dark Morris for another book (at least, I think I invented it), reasoning that since the year is round the seasons might need more than one push. Once, when I was on a book signing tour a Morris side turned up all in black, just for me. They danced the Dark Morris in silence and perfect time, without the music and bells of the ‘summer’ dance.
It was beautifully done. But it was also a bit creepy. So it might not be a good idea to try it at home …
Terry Pratchett