I always get asked about Central Park and even though it is not in Brooklyn it is a must see when you come into the city. I always wander around near Columbus Circle and then head East towards the Central Park zoo before heading up towards the reservoir. Here is a cool video I found that shows some other cool things to see in the park.
If you are going to walk around in Central Park make sure you bring comfortable shoes, a bottle of water, and maybe some binoculars as there are many types of birds.
