I don't think I need to mention that I like cool linkages. I found a really cool post on Make called "The mechanical glory of the IBM Selectric typewriter." For those of you who aren't old enough to remember when computers weren't really around yet, much less word processors and printers, a Selectric typewriter was pretty much standard in most schools and offices. I learned how to type on one and I also used one when I was a supply clerk in the Army. They were pretty amazing and if you found someone who could type really fast they could cause quite a racket.
And extra credit to the inventor of the linkage for the name...a "whiffletree" (Wikipedia)
Here's a short video of how they work.
On a similar note, I have worked with a machine that uses a similar style of printing using a large spherical print head except this one uses servo motors to position the print head rather than a whiffletree linkage. This is one of the many, many items on my "To Do" list. Not a great video to explain what is happening, but there are a few shots.