How to explain Open Source to a non-technical crowd

I've run into this great post from Jasha where he explains the differences between open source and closed-source software development by comparing software to food:

Closed source soup is served ready to eat in a bowl at the table by a waiter. Maybe not exactly what you want, but it fits your needs.

That's exactly right. With restaurants you get the convenience of being able to eat a delicious meal quickly, but you pay the price and the meal may not be exactly how you like it. With open source, on the other hand, you get to choose: you can go to a restaurant or you can make the soup yourself, or you can find a solution somewhere in between. The key word is choice.