If you've got a kid this smart, you'd better keep your head on a swivel.
This piece is based on two Quora questions. Links on the last page.
1. The Enigma Machine.
When my son was six, the 'rule' was if he wanted a new game installed on the iPad, he'd come and see me. He'd find one he liked and bring me the tablet. I'd decide if it was appropriate and, if so, enter the password and download the game. I'd always turn the device away so he never had access to the password himself. As expected, he always asked for the password so he could do it himself, but he never got it.
One day, he brought me the iPad and we went through the usual process. As soon as I handed it back to him, he smiled and told me the correct password. I must have looked puzzled. Fortunately, he couldn't resist telling me how he knew.
He'd found a game he didn't particularly want but which was childish enough that he knew I'd definitely approve of it. He then waited until I was standing in front of the patio doors and handed me the device, knowing I'd turn it away from him. Turning it away from him meant turning it toward the doors. That way, he could watch what I typed in the reflection on the glass.
I'm not sure if it's the smartest thing he's ever done, but it's pretty devious and impressed the hell out of me.
2. Lose yourself.
This conversation was between my dad and my sister when she was just 6 years old.
Sister: Why aren't you laughing, daddy?
Dad: I have a lot on my mind.
Sister: If you lose some of your mind, maybe then you can laugh.
If that doesn't perfectly describe the paradox of human thinking then I don't know what does.
3. Personally, I have all my big thinks in the bathroom.
I remember a night when my son (who is currently 13, and now in 7th grade) was still in kindergarten. I guess he was 6 years old. I was watching him as he was standing by the sink, brushing his teeth, getting ready for bed. He seemed to be somewhere else, lost in thought.
Then he paused for a moment, spit into the sink, looked up at me, and said something remarkable. (continued...)