Ok, this one is really cool, but is disguised by lots of text to read and monotonous dialog. It is full of very intricate mechanisms and well thought out gadgets. It's a marble machine, but the interesting thing about it is that the marble starts at the bottom and by the use of clever devices the marble is elevated to the top. It is made out of lots and lots of small pieces of wood and has taken the maker several years to make and perfect.
Do yourself a favor and watch this. The text ends at about 2:30 and then he shows the parts of the machine working, and then shows a full run at the end. It is about ten minutes long, but I am willing to bet that you will stick it out.
If you are still having problems sleeping after that video, visit his YouTube site at xeniaguy2's Channel. He goes into more details about how he built it and some of his other creations.