Can’t find the links to examples at the moment, but there have been many prominent installations that were interactive and responsive to the audience. I took a History of Electronic Art class in college, and we reviewed robotic / mechanical installations that react based on the audience. There was an installation of interactive ‘tentacles’ that hung from the ceiling, and would respond to a viewer approaching with sounds, warning the other tentacles of the viewer, and even move on their own, keeping a cautious distance from the viewer, while constantly observing them. It was really interesting, and almost soothing to watch, like a freaky fish tank.

Or, here’s another installation: A set of mechanical arms that selects photographs, actual family photographs, from a box, and then tears them up and throws them away. The user could stop the arms from grabbing and destroying the photos by holding their hand in front of a sensor, but as soon as the viewer removed their hand, the robot hands would resume their work, destroying photos.

Also, about a wall of colored panels, that light up in patterns defined by mathematical formulas, but only when a viewer touches a panel, setting the ‘seed’ for the formula.

Those installations are totally interactive, and if they didn’t receive input from the user, wouldn’t be nearly as interesting.

Every day the same dream
http://www.molleindustria.org/everydaythesamedream/everydaythesamedream.html

Auditorium
http://www.playauditorium.com

Which
http://gamejolt.com/freeware/games/adventure/which/1523/