According to a representative from the United States Postal Service, due to Hurricane Sandy, 11 Manhattan zip codes went without regular delivery for days last week, along with three others in Brooklyn, two in Jamaica, Queens, seven in the Rockaways, and most of Staten Island. This may mean that your absentee ballot didn't reach you until as late as Saturday or today. But if you can make it to the Post Office by 5 p.m. you can likely get it to the electoral board in your home state so they can toss it in the trash because you made a teensy stray mark outside the lines.
To see what time you have to make it to the Post Office by in order to send your absentee ballot, go here. As a general rule, folks on the West Coast, Hawaii, and Alaska have a bit more time, whereas East Coast voters have a firm deadline of 5 p.m. Bring cash or a credit/debit card: overnight mail by the USPS is cheaper than a private carrier, but will cost (at least) around $20. Find your nearest post office (and what time they close) here.
And if you're voting here in New York, your polling place may have moved. Look at the list below for all of the new polling places. If you're a New Jersey resident, find out how to vote by email here.