I don't normally post about rolling ball machines because they are a complete topic unto themselves with some great web sites fully dedicated to the subject.
This machine stands out for two reasons:
1 - It has wooden gears, so I HAVE to post about it.
2 - It is hand cranked like many automata.
Here's a link to the Marble Machine 2 page. I learned about it from the blog over at Make Magazine (my favorite).
Here's the video of the Marble Machine.