The 270-foot slide will be stationed downtown in Foley Square between Centre Street and Lafayette Street on August 1, 8, and 15. The massive waterslide is part of a partnership between Slide the City and NYC's free annual "Summer Streets" program, for which roadways are shut down for people to "play, run, walk and bike" (and now slide).
Those who partake in the fun will get an inflatable tube on which to shimmy down the slide, preventing what would probably be horrible road rash.
Below are pictures of other Slide the City events that will give you an idea of what NYC's slide will look like: