It's pretty neat that the Cosmopolitan turns their (4th floor) rooftop Boulevard pool into a skating rink in the winter- better than that, they surround it with firepits and add a food booth where you can get goodies like pierogi, chili, soup, and grilled cheese, not to mention a make-your-own-s'mores dessert kit!
Staff are friendly and reservations for the fire pits are encouraged- though they have a few available for walk-in business, the place IS busy so you shouldn't bank on getting one. Skate rental, socks, and skate passes available to enjoy the ice- glad that they have a locals pass to cut some of the fees.