Very cool art install in England by Richard Box called "FIELD" (via Boing Boing). Box apparently had fluorescent tubes placed in interesting patterns below high-voltage power lines. The tubes illuminate from induced voltage from the electro-magnetic field from the power lines. It's a very cool idea. (Note: I say "apparently" because Box's website is broken and I couldn't find any evidence that he actually did this other than lots of still photos).
Picture from Channel 4.
Picture from Gizmodo.