My five year old son came up with the best project, I had to share it. He decided to make his own Lego kit. He designed the model and drew the schematics. And then I was asked to complete it (which was a little harder than you might think).
Wouldn't it be fun to expand this activity to include the whole family? Each person who was into it could make their own kit, and then trade them around and see who could complete the project? This project works as well for pre-writers as it does for more fluent writers.
Have your Lego loving kids done something like this?