Best explanation you've got...

As crypto enthusiasts, from time to time I'm sure we have all had the problem of trying to explain our passion to someone whose eyes glaze over like a fresh donut.
While I have heard a number of good analogies, and read some good articles (like "How to explain Bitcoin to a 7 year old"), I am still at a loss with most people explaining what blockchain is and why blockchain technologies and digital currency are such game changers. Can we try to crowd source an answer that would give some sort of simplified, unified explanation of cryptocurrency and blockchain to the average brother, coworker, or uncle? Something with concrete examples that would stand them half a chance of actually grasping the content without having to be versed in computer code or algorithms. I realize this may be an impossible task and I may just be tilting at windmills, but if anyone can tackle this challenge, I think this is the right group.
Please share your best analogies and explanations, thanks !