Level of sneak difficulty: Hard
How to get in: This rooftop pool is also accessible only during the day, and all floors need the power of a room key. Unfortunately, I arrived on the scene after-hours, but I was told from an inside source (let’s call him the Deep Throat of hotel pools) that if you can get yourself to the top floor, the stairs lead directly up to the roof and to a pool that has 1) pretty kickass views of lower Manhattan, and 2) its own bar. So yeah, it’s time to whip out your social skills and make a friend again.
Also: if you happen to go after-hours, you can still drink at the bar, The Jimmy, and stand next to the pool. But be forewarned -- there's a bouncer there who told me in no uncertain terms that if you jump into the pool with all of your clothes on, he will definitely throw you out.