In order to teach about the benefits of long term savings (in general) and, more specifically, of employer contributions through 401(k) plans, we have established for our first born (12 years old) a 401(k)ar account. The deal with this plan is that whatever money he puts into it, we will match 100%. He's 4 years away from getting a car, so I figure if he can put $25/mo into it that'll be about $2400 (after we match) over 4 years. That ought to be enough money to get a good beater-up car for pretty low insurance costs.
And I'm so proud of him. He took the $50 that he received from his Grandma and put it in the account. So he's got $100 in there now.