Here in Lafayette County (at least at my precinct), we use optical mark scanning machines. You fill in the ballot with a Sharpie, filling the little bubbles next to the names of the people you want to vote for, then you feed it into the machine that scans each ballot, checks for overvotes, and dumps it into a hopper (actually, I think it’s just a cheap plastic trash can, but it makes me feel better to think of it as a hopper) in case it needs to be consulted later (either due to write-ins or a recount). The machine’s a little slow, and I’d be slightly happier if the guy supervising the machine couldn’t get a glimpse of your ballot (however, he seemed to be doing a decent job of averting his eyes when I went to vote in the primary run-off late in August), but it works, and it makes sure the original ballot’s available in case there’s some controversy down the line. I don’t know how it would work with a multi-page ballot; I guess you just feed it in a page at a time. Some precincts, though, apparently have the ballots counted at the main office after the polls close.

Elsewhere when I’ve voted we used the now-notorious punch cards (when I lived in Florida—even when you voted absentee, you got a punch-card ballot along with an implement that looked something like a bent paperclip), some sort of ancient button-based contraption (Shelby County), or a touchscreen which used some sort of smart-card in the process (Shelby County again—originally they were only used for early voting, I’m not sure if they’ve started using them on election day too).