I found some lectures on Open Yale that I used to supplement our first few lessons. From those we were able to discuss exoplanets and the geocentric model in-depth.
These last few weeks we've been working from a book studying the sun, Mercury and Venus.
We've even thrown in a few experiments. The purpose of this one was to use the butter as the representation of the rock (a solid), melt it on the stove (to form the liquid) and then pour it over a cup onto flour to represent the lava running onto the surface of Venus.
After letting it sit a while, we came back to feel the surface once the "lava" had cooled.
And because Jack is so into planets at the moment, I'm trying to plan some cool daily or weekend trips in March or April. There's a planetarium nearby. I've heard great things about the Tellus Science Museum in Cartersville, GA and want to include that on our list. There's also a Space and Rocket Center in Huntsville, AL that would be great to visit at some point along the way.