Forgotten NY is essential for anyone interested in the vast, curious and, indeed, forgotten past of this extraordinary city. The website is, admittedly, a bit overwhelming at first, but random browsing is sure be rewarding.
Divided into categories like cobblestones; cemeteries; “You'd never believe your in NYC“; Queens crap; and subways & trains (also see this week's what to do with a couple minutes), you can find all sorts of little slices of history right outside your door.
Look up your neighborhood and start exploring, though it's worth noting that since the city evolves and changes so rapidly, some information might be a bit outdated. But, if you have updates, feel free to contact Forgotten NY to keep everyone in the know.
The site, created by city history enthusiast Kevin Walsh, is considered the go-to place for quirky historical NYC info, and I've yet to find anything that's nearly as expansive. Just like the city Kevin and his contributors obsesses over, the site itself keeps expanding and now there's a Forgotten NY book (the making of which is detailed in an online diary)–and they also lead tours 4 to 5 times a year (keep an eye on their site to find out when the next one will be scheduled, I will be!).