The Unknown Family just went to the polls and voted. Unknown Son went into the booth with me, and Unknown Daughter went in with the Unknown Wife. We let our kids fill out the ballots (they were paper ones), and then feed them into the machine.
It's pretty cool explaining how our political system works to an 8 year old and a ten year old. This year, I think I'll start working through the Declaration of Independence, the Constitution, and the Bill of Rights with them - it's never too early, and most people (myself included) don't know enough about these foundations of our country.