Like, for example, become aware of the impact this year’s presidential elections will have on their lives, four years down the road, when those who are now 15, 16 and 17 (not old enough to cast a vote) will be 19, 20 and 21. Old enough to feel the impact of something they had no hand in bringing about.
Or, if they are really clever and handy with HTML and CSS (and have an eye for style to begin with), they might build a website devoted to this very thing.
Go visit Voice Your Vote. And tell all the teens you know to go visit it, too.