Check this video out. These machines are simple in what they used, but really genius in the design. I am working to make a simple one with my 3 and 4 year old sons to teach them some simple mechanical engineering. They loved watching the video clip.
If anyone reads Japanese and knows what the messages are at the end of each machine - please post.

Seriously, this is one of the coolest videos of its kind I've ever seen. The ingenious design of these miniature setups are incredible to watch.

Yea, I've watched this like 10 times in the last month or so. These take ingenuity, creativity and intelligence. A rare combo in most humans.

Oops...forgot to mention that the original video is gone. The new location for the same video is here.

Aw, fun times! It reminds me of cartoons when I was little.
I lived for the chain reaction sequences! I also liked any game
that had this kind of thing in it (like MouseTrap).