Are you registered to vote? Here in Utah, Friday is the last day to register online: https://secure.utah.gov/voterreg/index.html
Here are some other key dates to keep in mind:
Online: Oct. 23
By mail: Received by Oct. 23
Absentee ballot deadlines
Return by mail: Postmarked by Nov. 2
Return in person: Nov. 3 by 8:00 p.m.
Oct. 20 - Oct. 30, but dates and hours may vary based on where you live