STOC is a data visualization of the S&P 500 from the NYSE programmed in Processing. Each circle in the visualization represents one of the stocks in the S&P, with characteristics of each visualizing different data points for each. There is a legend in the project that will explain the relationships between data and visuals, as well as a list of the controls for interactivity.
Whilst the project is not meant to be used to do any trading on the actual stock market, primarily for not being realtime, it is nevertheless an interesting/ alternative way to understand relationships between different stocks.
You can find out more about the project here as well as download app available for Mac, Windows and Linux.