Both of these tools were recently released by Utah State University under the GPL license. You can read more about them by following the links, including sample movies that demonstrate how the tools work. The tools were created by Rian Shelley.
IPVisualizer
IPVisualizer is a visualization in which a range of IP addresses are represented as dots on a screen. The shape, intensity, and color of the dot indicate the direction, count, and type of the traffic, respectively.
OIP
OIP is a visualization in which individual machine IPs are placed randomly on a display, and packets are visualized as different sized dots flowing from one machine to another.