"Grade Distribution" used to be a great way to explain taxation and income and wealth distribution to kids who've never had a job. Sports examples work well, too.
Usually, they know how hard it can be to EARN a good grade, especially in a difficult subject, and they usually are also familiar with slackers and with getting poor grades from not doing the work.
Unless they are a natural born slacker, the idea of taking their hard earned As and distributing them to the rest of the class so that everyone else gets a B usually makes them unhappy.
It's good to learn this lesson early. Our world would look much better now if more had.
Oh well...maybe a future generation will benefit from our example: From landing on the moon to crazier than a loon in less than half a lifetime! How fast and how hard the once mighty fall.
Everyone gets a diploma!
Next up, salaries.
I've used that an example to teach my 6th graders what socialism is all about. I only have them for an hour once a week during the school year, and our Old Testament curriculum is packed.
When I take 20% of hard-working Maria's 100% to give to slacker Jimmy's 60% to "even things out", they get the point very quickly. lol