Open House New York weekend is coming up in 7 days and NewYorkology has a handy guide to which places you'll need reservations for this (the 5th) year, check it out here. Touted as America's largest architect and design event, OHNY opens usually locked doors throughout New York City each October (and sometimes Spring).
Discover new nooks in each of the five boroughs through special talks, tours, performances and workshops. The weekend is free and this year has over 300 sites and programs open for participation.
Some picks: A 19th Century row house in Carroll Gardens (pictured), an MTA substation in Brooklyn and some old theaters in Park Slope. Green-Wood Cemetery is definitely worth a visit if you haven't already been there. And the World's Fair Architecture Walking Tour is a must since some of the structures there were put on the endangered list earlier this year.