The average college grad goes through eight different jobs in five different cities before age 30*. It can be hard to remember if–and where–you're registered to vote. So check your status at Votepoke and register if you need to. It's paid for by MoveOn.org but the site itself is free of political bias (although you have to opt-out of a "progressive" newsletter).
While we're on the subject, we also maintain that election days should be holidays.
*We made this up but it sounds plausible.