I've found it damn near impossible to explain what crypto is without getting technical. I'm not sure if it's possible, and that's one of the hurdles we'll have to face getting people to use or trust it.
The only advice I have is to cut out any technical terminology - like blockchain, or decentralized...if you can find a way to do that, you'll get fewer blank stares. But again, that would defeat the purpose, wouldn't it?
@aussieninja pretty much nailed it.