I enjoy projects in which art emerges from a simple idea. In this case, Ken Murphy, a "musician, programmer, artist, and tinkerer living in San Francisco," created a system on the roof of the Exploratorium to capture the sky every day with a time-lapse camera. He then combines the result into a whole that reveals something new and mesmerizing.
Looking at the time stamp in the lower right corner of the video below, you can guess at the approximate time of year of each square -- I had expected January to begin in the upper left, but this doesn't seem to be true. As it is, the grid is 20x18, which means each month takes up about 1.5 horizontal lines. I've only seen the video, but some of the other examples of installations on his website look even more compelling.