Was talking to a friend/relative/client this week, who asked me to explain Bitcoin, and where it derives its value from.
Once we covered the obvious supply/demand, we discussed scarcity. When trying to wrap his head around why no-one can just create additional Bitcoins out of thin air, I explained with an example of Prime Numbers, and then further explained the concept of blockchain, which essentially creates a "pedigree" for each Bitcoin.
When all was understood he proclaimed: Aha, so Bitcoin is gezhe currency!