I thought it might be helpful to report on visiting the Rain Room, in the empty lot to the West of the Museum of Modern Art. Checking for previous posts here, I was found this report of the same, or a similar exhibition in London last year:
The only entrance to the Rain Room is though a chain-link fence on West 54th Street, slightly West of the museum itself. Members only have to bring their card, but if a member has guests, they have to buy the guest tickets at the lobby Membership desk, just like you would to enter the main part of the museum. Than means that non-members should have a ticket before they get in line. They put steel crowd barriers along the fence, leading the line east on 54th Street. There's a shorter line inside the building, since they only admit ten people to the rain field at a time. This also lets your eyes adjust to the relative darkness of the interior.
I had to put earplugs in on line because there was a street crew using a 32" carbide saw to cut pavement on 54th Street!
Guests are advised to remove shiny outerwear because it can prevent the sensors from seeing that you are under a rain outlet, and thus you might get wet. I found that if you walk slowly, you indeed don't get more than a few drops on you the whole time you're in the rain field. I did not have to check my shoulder bag. Photography is encouraged, but the darkness and the glare of the single theatrical HMI Fresnel, about ten feet off the floor, makes getting a good picture difficult.
One reason they only let ten people into an area about 1/3 the size of a basketball court is that the rain leaves you an empty circle a bit more than a meter in diameter. That means that two people standing two meters apart can hold hands without getting wet.
Although I don't question for a minute that Diller and Scofidio's "Blur Building" in Switzerland was "art", I'm not so sure about this. It's a clever parlor trick, at least.