Nuit Blanche took place here on Saturday night, and this was my favourite: Project Blinkenlights' Stereoscope exhibit at Toronto City Hall.
Project Blinkenlights are digital performance artists (Tim Pritlove and Thomas Fiedler) from Berlin, Germany. More project info here.
In addition to the visuals in this clip, they rigged up gigantic classic arcade games of Pong and Space Invaders that any two people can play using their regular cellphones. Pretty amazing stuff!
Artists' website: http://www.blinkenlights.net/