To follow up, we posted this last night just before bed time. When he woke up this morning, I showed him how many comments there were in this discussion and showed him the page you created. He got a huge smile on his face.

By the time I left for work, he was playing Rescue Heroes with his brother. :)

Thank you, everyone, for the words of encouragement and the constructive criticisms. I agree that just mindlessly praising anything a kid does can be bad, and I immediately thought of many of the criticisms raised here when my son made told me his idea. However, I wanted to present his idea without any editing or adornment on my part, because then it wouldn't be his idea any longer.

I will definitely save this discussion and go over it with my son again later when he's better able to grasp the arguments. I find that, when introducing a new idea, it doesn't seem to totally "take" at first. However, a few days later, it somehow has been fully absorbed and he's able to generalize and make appropriate inferences from the idea.

Thanks again!