Lennart has a nice writeup on automatic differentiation in Haskell. I keep trying to come up with a reason to learn more about Haskell, and examples like this (which are difficult or at least less understandable in C or C++) go quite some way in convincing me that I should invest the time to understand how lazy, functional, polymorphic languages like Haskell can change the way I write programs.
Caught Sam's cat on the wireless webcam, but mostly this is just a test of the embedded flash player.
Addendum2: You can create flash video using only open source, free tools. I took the AtomBomb1946.mpeg from archive.org, and then ran:
ffmpeg -i AtomBomb1946.mpeg -s 320x240 atombomb.flv
and then just created the viewer: