The boy and I were strolling through some shops in downtown Saturday evening. He was drawn to a pleasant, simple, little bird house. He asked to buy it.
"We coooouuuld buy it, but wouldn't be more fun to make one?"
We made two actually.

We sketched out our design and measurements together. We laid out the cuts, I operated the saw, we drilled and assembled. Hole in the door is 1 1/4" in diameter (my largest paddle bit). We drilled pilot holes for the the screws so as to not split the wood. We used a larger bit to drill 1/32 or so down the top of each hole to counter-sink the flared head on the screws so they would be flush with the face of the wood. We used both screws and wood glue.
For the swinging clean-out door (a feature we lifted from the model at the store) we used a drill bit the diameter of the shaft of our screws to drill holes in the sides. This allowed the screws to pivot freely in the side panels while screwing securely to the sides of the door.
The boy learned a rip vs. a crosscut, how to set a fence on a table saw, some spacial reasoning, how to follow a plan, how to recover from a goof or two, and how to see a project through, among other things.
He had a great time. I had even more fun than he did.