Most New Yorkers will tell you they love to explore different neighborhoods on the weekend. Typically Spring and Fall are best for these activities because you can avoid the extremes of 30 degrees and windy in the Winter or 90 degrees with 100% humidity in the Summer. I like to bring my Nikon D5100 with me but half the time end up using my iPhone to snap some pics.
A few neighborhoods I like to visit are the South Bronx, Astoria in Queens, Brooklyn Heights and Financial District in Manhattan. I am always up for a quick ride on the Staten Island Ferry as well.
No professional set-ups are required. Simply grab a coffee, keep your camera or phone ready and just pick a few avenues and side streets to walk down. This is a perfect activity to do with local or visiting friends and you can compare the results over drinks once you are done for the day.