You technically arent allowed to smoke or vape anything in public parks but people do. Astoria Park on 4/20 4:20 this year was a low key neighborhood sesh.
On the street, all times of day. I read that NYC has the highest (snicker) cannabis consumption of any US city right now. The streets are positively littered with the foil backed smelly proof bags lately. If we're lucky, maybe cheap sheets of LSD will return to Central Park in a few years.
Of course a prime location was always inside/outside many music and entertainment venues over the years. I smoked an entire joint on the edge of the stage during Les Claypool and the Holy Mackerel at the Supper Club during the liberal use of a smoke machine. Near the end of the joint the guitarist sat on the edge of the stage in front of me so I blew big clouds over his guitar while he played. Just when I got to the roach a security guard saw me so I tossed it and showed him empty hands....
Vaping has made getting high in venues even easier. With a little slick maneuvering, you can get in a fair amount of hits without drawing attention. A really easy one for any place with a bathroom (especially a big one like a stadium), is to vape in the stall and blow the hits down and out with flushes. It's not dignified, but you likely won't get caught.