I have to say I have a weakness for what are commonly known as “Rube Goldberg” machines. The name refers to an American comic artist who created crazy contraptions to do ordinary things. Here is the official Rube Goldberg web site, if you’re really interested.
Of course, there is the wildly popular music video (8 million + views on YouTube as of this month) by OK Go, “This Too Shall Pass” which is based entirely on a Rube Goldberg machine that provides the visual thread for the song. I like the way it gets bigger and more out of control as the song progresses. And it must be fun to destroy pianos, TVs, etc. It lost some of the purity of the machine as it got more crazy; you lost some of the actual mechanical connection and they could have faked lots of it if they wanted to. This is just one recent example.
I also loved the Honda Accord commercial from 2003. While not as wild as the OK Go video, it has a more pristine, controlled, elegant feel to me. When I saw it for the first time, I was blown away. Wikipedia has a complete description of the commercial, its production, and impact for Honda. 606 takes over 4 days to complete; that’s insanity.
There’s a cool parody of the Honda spot, just for fun.

The ones I’ve seen tend to be in commercials or music videos, but what about such machines in narrative films. I cant remember one off-hand. I wrote a Rube Goldberg machine into a script I did back in 1996 or so. It was for an educational video series I wrote and directed for Moody Video called, The Newtons’ Workshop. The main character was an eccentric inventor or sorts, with a passion to teach his grandkids about science. My production designer had a fun time constructing a mail delivery system for Grandpa’s house. We were not skilled, well financed, or patient to make it all work perfectly in real life, so we used creative edits to make Grandpa’s machine work on film. I don’t have a clip, but I’ll post it sometime when I can get it digitized.