The Stock Ticker Orbital Comparison, or STOC for short, from media student James Grant, uses a planetary system metaphor to display activity with the S&P 500. Each circle represents a stock and they orbit a planet-like (or sun?) thing in the middle.
Color, size, and transparency represent percent change, market capitalization, and moving average, respectively. Percent change relative to the rest of the market determines the speed at which a stock orbits - fast movers so to speak.
Here is the video demo with techno-ish background music and all:
You can also download and interact with the prototype yourself from the STOC site.
From an aesthetic point of view, it's pretty and fun to play with. I can see it running in the background in some futuristic stock market movie. From a more practical standpoint, I'm not so sure, but that isn't what STOC was developed for.