Jeppe Hein's - "Mirror Wall", from the "New Art From Germany" exhibition, at the Saatchi Gallery, London.
December 2011.
When you walk past the mirror it vibrates, as you can see in the video.
Saatchi Gallery: http://www.saatchi-gallery.co.uk/
http://www.saatchi-gallery.co.uk/artists/germany_art/
Bonus track: http://www.youtube.com/watch?v=myj-RhUqMtY