Just west of Heckscher Playground is Umpire Rock – or, as it is known to climbers, Rat Rock. This is the bouldering center of Central Park and draws thousands of rock climbers every year. The climbing surface consists to two separate faces on a very large boulder and features the most popular and difficult climbing in the park. It is also an excellent meeting place for climbers who are seeking partners.
More useful info about this sport that is gaining in popularity every year can be found here.
Location : Mid-Park at 63rd