Hurts my brain! Non-circular gears.

Wish they showed more... the "main" one just reminds me of a Wenkel...

http://blog.makezine.com/archive/2008/09/noncicular_gears_in_actio.html?CMP=OTC-0D6B48984890

http://www.8625plus2.com/products/NCG-Video-en.htm -- I had to use IE on that one, FF didn't like it.