The notes for the third class are up on the Spooky Arduino class page.
Also are links to many of the Arduino code sketches used in the class.
Here’s a 10-minute project that’s a glowing orb thing similar to the Ambient Orb (but much larger!) using the techniques from this week’s class.
[Update: there’s a more detailed post about how the orb works]
I love the reference to The Orb’s “Little Fluffy Clouds” song in the video.