Hudson Yards: Climb the Vessel (free but grab a reservation online) and eat at the Mercado Little Spain (Spanish version of Eataly)
JP Morgan Library & Museum: really cool view into life of the rich and powerful from the early 20th century with a Guttenburg Bible thrown in for fun. If you like art architecture and books this is a must stop. Audio tour is included with admission and strongly recommended.
Bryant ParK is always fun especially on weekends. Be sure to step into the NY Public Library for a look around. Not your basic neighborhood library.