The graphic designer Rudolph de Harak created a three-story digital clock installed on the exterior of 200 Water Street. The clock consists of 72 square modules with numerals that light according to date, hour, minute and second.
You've heard about the reading room at the New York Public Library, haven't you? Then I need not go on. Just look at it. And you're allowed to hang around in there!
The permanent piece called "Meeting" at MoMA PS1 is an etherial experience of light and color and quiet. Sit and look through the cutout in the ceiling and watch the light change both outside and in. You can't tell what you're looking at until maybe a bird flies by.