About 15 minutes in Ward 19, Precinct Q in Cleveland, Ohio. I arrived at about 12:20
PM and there were five people aheard of me.
The people there were extremely careful - not only did I have to sign the book as usual, but they also wrote down my name and address, along with a ballot stub number, in a separate book. The stubs are removed as the ballots are placed in the box, so individual ballots still can't be traced back to the actual voter; but the number of stubs has to equal the number of ballots at the end of the day.
Here in Ohio they told people that if they arrive at the polling place before closing time, they will not be turned away. But if you're not in line by closing time, you lose.
By the looks of things, there's going to be record turnout for this election.