the temporal values - from minimal to video exhibit at zkm looks interesting. artists include peter campus, sol lewitt, nam june paik, bill viola, peter weibel, and robert morris, untitled (mirrored cubes), 1965

monica bonvicini's don't miss a sec, 2004 at the tate modern, a public panopticon restroom. the stall walls look like mirrors from the outside, and windows fron the inside.

henrik plenge jakobsen, laughing gas chamber, 1996

and two cell phone public art pieces:

usman haque, sky ear, on may 4 (lunar eclipse) a glowing "cloud" of one thousand mobile phones and helium balloons will be released into the air. people can dial into the cloud and listen to the "sounds of the sky", while their calls affect the electromagnetic environment inside and change the balloons' brightness, colour and intensity
peter freeman, spectra-txt, a 30-foot stainless steel beacon changes color by having a text message command (such as blue, starvibe, xxx, pearl, boro, and chromapop) sent to it