Mobius sez, "My friend Martin took the NYC MTA's Subway Advisory Alerts and made RSS feeds for each individual train. The URLs link directly to PDFs of the same posters the MTA hangs in the subway stations. Comes in pretty handy if you're used to MTA service sucking ass. Throw a feed up on your desktop aggregator or on your blog (as I have done at sexveggie.com) and you'll never get stuck waiting a month for the train again."
(Thanks, Mobius!)