Murmur — From sound to light, by talking to walls. By Chevalvert.

Murmur is an architectural prosthesis that enables the communication between public and the wall upon which it is connected. The installation simulates the movement of sound waves, building a luminous bridge between the physical and the virtual worlds.

Installation pour la Nuit numérique #10. Centre Culturel Saint-Exupéry, Reims.

Urban Echo by Christopher Baker, presented @ Huset i Magstræde, Copenhagen, Denmark, 2007

Urban Echo is an ongoing series of interactive sound and video installations. The project has appeared in many forms ranging from intimate outdoor video sculptures to large interactive public façades. Urban Echo aims to collect and creatively represent the
thoughts and imaginings of city-dwellers.
In each installation, participants send their thoughts and questions via SMS and voicemail. The responses are then projected and added to a dynamic spatialized audio composition.

Music: J. Anthony Allen http://janthonyallen.com.
Concept: Christopher Baker http://christopherbaker.net/projects/urbanecho/

UUUU_002 by silicat

Fight by Steven Subotnick.
A showdown between two motley characters.

"Sandbox" at Santa Monica Beach (2010) by Rafael Lozano-Hemmer.

"Sandbox" is a large-scale interactive installation created originally for Glow Santa Monica, CA. The piece consists of two small sandboxes where one can see tiny projections of people who are at the beach. As participants reach out to touch these small ghosts, a camera detects their hands and relays them live to two of the world's brightest projectors, which hang from a boom lift and which project the hands over 8,000 square feet of beach. In this way people share three scales: the tiny sandbox images, the real human scale and the monstrous scale of special effects.