If you are in New York, a visit to the MOMA is a downright must, offering amazingly curated collections along side classic works of art. My suggestion is to take advantage of their admission-free Friday evenings—the line may in fact stretch around the block at times, but it does move quickly (and even if takes an hour, then consider that a $25 per hour job just for standing in a queue).
This was my favorite experience by far: "Play Dead," by Douglas Gordon. I want you to experience this for yourself, so I won't say much else, except that the YouTube video doesn't do it justice at all. When you go, be brave and lay down on the floor, on your belly. Experience the ambiance, grace, and fluidity—just how I believe the artist originally had it in mind.
Free admission is from 4:00 to 8:00 on Friday evenings.