We just returned from the early kid-friendly part of an all-night across-the city art event here called Nuit Blanche. It was almost enough for these kids that they were out after dark, let alone seeing art! One cool thing was called "Glow-worms". Basically, a large scan of a local park was filled with hundreds of flashing bicycle lights at about knee-height, randomly placed across the grass and under trees. Kids loved it.