http://en.wikipedia.org/wiki/Election_Day_%28United_States%2...
http://usgovinfo.about.com/od/thepoliticalsystem/a/whenwevot...
I point this out to anyone who complains about how archaic some things in the UK or Europe appear to be.
However, in this country there is a constant struggle between trying to let more people vote versus trying to restrict voting. Hence why a lot of people are up in arms about potential voter fraud. The traditional wisdom is that more voters helps one party, fewer helps another. With this as a factor, you can see how it would be very difficult to change the day of voting to make it more convenient for people.
The date is set by an act of Congress from 1845.
http://memory.loc.gov/ll/llsl/005/0700/07590721.tif
I think my other arguments still stand though...
An alternative, as it's done in Spain, is to give everyone the right to leave their jobs in order to vote. To alleviate things for businesses, all elections happen on Sundays.
That just sounds like a lazy excuse to me. I don't know how long it takes to vote in the US, but where I live in Canada, we just finished our municiple elections. It was one of the longest ballots I can remember, yet the entire process, including walking from my house to the polling station and back, took about 20 minutes after work.
I have to say, I just don't understand this voter apathy or this sentiment that if none of the candidates are any good then don't vote. I really do think it is your duty as a citizen.
And don't forget Gerrymandering, in which the party in power redraws the voting district lines to ensure that every district has a majority of their party (though that happens before election day): http://en.wikipedia.org/wiki/Gerrymandering
Edit: I added a few more examples from other replies that represent common methods of intentional sabotage.
Broken electronic voting machines.
Higher than expected turn out resulting in a backlog.
Showing up after work along with a huge group of people doing the same thing.
2 of the 6 machines the precinct received did not verify when turned on. They're an electronic booth with paper printout (yes,what the vote hackers wanted to begin with). However the paper did not agree with the electronic tally, hence machine invalidated.
And they got 4x the turnout they were expecting. Now, usually, it's 20 min in line and 3 min for the vote itself.
We effectively do have a "none of the above" option: don't select anyone and still cast the ballot. However, it would be better if there was an explicit "No vote" option.
The biggest problem with voting not being mandatory is that a lot of people don't have the opportunity because they can't get off work. If you made voting mandatory (or at least made election day a paid holiday), this impediment might be alleviated.