I think i just thought about my favourite explanation (for now) of what is bitcoin is. I imagine the following scenario between two friends, Bitcoiner and Nocoiner.

BTC : Hey man, check this project out

Nocoin : What Project?

BTC : Bitcoin.

Nocoin : Whats it all about?

BTC : Imagine that we all decide to store a database of who owns what. Imagine that we do this in a really legit way. Imagine that we store a copy of that same database in many milions of computers all over the world in a decentralised manner.

Nocoin : Is that what bitcoin is?

BTC : Much Much Much more more than that. But thats a good place to start.