Mom had the idea. Dad had the car, the tape measure and he knew where Lowes was. Most importantly, he had a method of payment.
Then we spent a Saturday at Grandpa Duckys (after spending a Friday night there) and Grandpa showed us how to make the plans for the planter window box that Mom wanted. We then went to the store with Ducky and got all the materials and Ducky spent an entire afternoon showing Dad how to do it.
The result is pretty much exactly what Mom wanted (well, she wanted it twice as long but the physics of the car prevented that) and we brought it home and stained it. There was a period of time where we kicked around the idea of putting some painted decorations on it, but it looks better as a simple box.