The Mamushka

The movie treats the Mamushka as one of these, taught to them by Cossack cousins so long ago they no longer remember when. And since Gomez explicitly states that they danced the Mamushka while Nero fiddled, that means the Addams family has been around for at least nineteen centuries, and has documented enough of their family history to know exactly what they were doing the night of July 19, 0064. That's how old that traditional dance is.

Example of:
Ancient Tradition