I realized that putting all of the Pinewood derby pics into one post would be pretty photo-heavy, so I will post the building of the cars as a little tease.
Being an engineer, it was pretty tempting for me to want to tell them how to build their cars, but it is really important that they learn the how and why. The race isn't about winning - though that is the goal. It is about learning and having fun. BUT when there are power tools and xacto knives involved, the adults do need to help them out.
We spent one Saturday googling images of Pinewood Derby cars for ideas. Then, they set to work building the cars... (The grown-ups helped with the power tools and sharp objects.)