Visit Bryant Park Winter Village. See the Rockefeller Center Christmas tree. Attend the New York Botanical Garden Christmas train show, Bar Car Nights. See the city (with a beer in hand) at One World Observatory.
If the weather is inclement or if you need a break from the outdoors but still want to find some fun things to do at night in New York, an escape room is a great option. There are more nighttime activities in New York City than just clubbing or going from bar to bar; watching a comedy show is a great option if you're looking for something to do after hours. The best way to see New York at night is to take a tour; I've always preferred to walk around the city, but there are a LOT of options to try, and each one has something that makes it unique. If you want to try something a little out of the ordinary when looking for things to do at night in New York, you can get tickets to The Moth.
I wouldn't recommend it in winter, but if you're visiting in the summer and don't know what to do at night in New York, take a walk and see the city from a whole new perspective. Whether you're the world's biggest fan of Ru Paul's Drag Race or you've never heard of it before, if you're looking for fun things to do in New York at night, head to 227 E 56th Street and spend the night at Lips NYC. If you're visiting New York during the summer, another more exclusive and local thing to do at night is to enjoy the attractions at Luna Park on Coney Island. The Lower East Side has fascinating nightlife and so many unique spots close together, making it an ideal neighborhood to go from bar to bar while taking in the views from the rooftop, making it a great spot for NYC date night ideas.
A great romantic and less touristy activity to do at night in New York is to see Ballet, Opera or even Jazz at the Lincoln Center for the Performing Arts. When all else fails, sometimes it's best to stick to the basics, and bowling is an easy and fun nightlife activity you can do in New York.