Explaining the Bitcoin software

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Q: Bitcoin has two aspects to it that make it unique - software and economics. 
Can you explain a bit about the software to us folks that can’t code?

A: A protocol is a set of rules that participants agree to. For example, 
when playing a sport, the rules of the game would be the protocol. 
Bitcoin is a protocol enforced by software that can be run by anyone. 
You can run a node that connects to other nodes over the internet. 
Nodes verify that transactions (sending and receiving bitcoins) 
follow the protocol rules, and reject the ones that don’t.

To prevents participants from spending the same bitcoins twice, 
the transactions are grouped together in a block and timestamped. 
This job is done by the miners, who use specialised hardware to 
compete against each other. The first to find a correct block 
wins the reward and all the fees paid by the transactions 
inside it; then all the miners start over.

It’s important to note that while miners do consume a 
lot of energy, the node software can be run on normal 
computers and consumes less electricity than your web 
browser. This enables the Bitcoin network to be highly 
decentralized: the protocol rules are jointly enforced 
(and thus determined) by a large community of people 
around the world.

I'd stress the protocol a bit more because it might be valuable for explaining other things later on. Sports is already better than gifts. What about:

Seeing a red light while driving should make you stop until you see a green light again. If you want to redeem a collection-only check, it needs a valid signature. In the first case, it's easy to violate the rule but you'll get punished if you violate the rule. In the second case, you simply can't remove that rule if you want to redeem that check.

And later: For sure you can violate the consensus of traffic-lights (1mb blocksize) but you might get punished by removing you from the "public". If you want to redeem your check without a signature, you have to commit fraud one way or the other or you have to put up parallel system which is accepting unsigned checks. Good luck with that.

I'm sure there are better analogies and analogies always fail sooner or later but at least they can carry the point for some time and better analogies would carry the point better or longer.

I currently don't have too much time for this but maybe it inspires somehow ...

Bitcoin is a messaging platform for value messages. It’s not money, but it replaces money.
It’s like email back in the 1990’s. Emails were not considered mail, but they replaced mail.