The Open House New York event is the concluding "upload party" to the Wikipedia @ Open House New York Weekend photo scavenger hunt, and an accompanying Wikimedia Commons tutorial and multimedia hackathon.
Learn how to work with your photos to illustrate New York City articles!
Note that this is part of the larger Open House New York Weekend activities on Friday, Saturday and Sunday, when sites normally closed to the public are open for public visits and photography.
If you can, bring your camera/photos to the event, and a laptop if you'd like to engage in adding photos to articles. But this is not necessary.