Gil's LotD
http://wificamera.propositions.org.uk/ A cool project that consists of a homemade cantenna and a projector which projects the wireless networks as they are observed by the antenna.
http://www.youtube.com/watch?v=pv5zWaTEVkI Another home music video by the band OK Go.
http://www.youtube.com/watch?v=DjCL0_0Il7w The same music video, done with legos.