What is a "thing", anyway?

So here's the problem with playing 20 questions with a five year-old...

Inspired by Rhett and Link's current road trip video, my five year old and I decided to play some 20 questions. The five year-old wanted me to guess first.

Is it a thing? No
Is it a person? No
Are you sure it's not a thing? Yep
It's not something I can touch or taste or smell or see? Oh wait, it is.
Is it something in our house? No
Is it something outside our house? No
So it's not in our house or outside of our house? Right
So what is it? Our house.
D'oh. Should have got that one.

Now I've got one for him to guess. He clearly doesn't understand the guessing tactics but ventures some guesses anyway:
Is it an insect? No
Is it the couch? No
Anything in your body? No
Is it the piano? No
Um, what is it? The school

He wanted some revenge so I'm up for guessing again.
Is it a thing? Um... Yes.
Do you know what it is? Yes
Is it inside our house? Yes
Is it on your body? No
Is it in the living room? Wait, is this the living room? Then yes
Is it a piece of furniture? Mmmmm, no.
Do you know what furniture means? Yes
Is it something you're standing on? No
Is it something you can hold in your hand? Yes
Is it on a bookshelf? (He looks at the piano) Um, no.
Is it on the piano? Yes
Is it your piano book? Yyyy-yes!

See the video that started it all here:
http://www.youtube.com/watch?v=LsoIQAgi8fg&feature=channel_video_title