So some scientists in London rebuilt an ancient Antikythera mechanism (http://en.wikipedia.org/wiki/Antikythera_mechanism), used to predict the movement of the stars, moon and Sun.
What is remarkable about it is that it dates to about 2000 years ago and is surprisingly complex for the time, including many small
and fine gears.
Here's a video of the newly constructed one: http://www.youtube.com/watch?v=ZrfMFhrgOFc (http://www.youtube.com/watch?v=ZrfMFhrgOFc)
The question is, how many days are in those "months" and how many months are in their "year"? lol