Hi there
What's the most simple way to describe what bitcoin is for people?
Will be cool to read in the comments some new creative ways to do that!

It is hard to explain to a 7 year old kid what is bitcoin, and I think even if how simple you will say it to a kid they will never get interest with it. Imagine how hard to explain it to an adult and still they are not all interested with bitcoin. So, maybe it will still depend on a person how interest they are to bitcoin before they will understand bitcoin fully.