Would you call the 'Langton's Ant' prgram (and other variations on it) an emergent system? Although too simple to call the patterns that can emerge 'behaviour' as such, the incredibly simple rules produce unexpected complexity.

subsumption archiecture is great for acheaving emergant behaviour.

Your AI consists of several layers all connected to sensor information and motor output.
A lower layer can override a higher layer, and every layer should have a single objective.

Example of layers from bottom to top:
Avoid - Avoid crashig into stuff
Wander - Keeps the robot wandering
Pickup - Pickup anything that it wants
Inspect - Stear towards anything interesting
Explore - Steare toward a distance place
Boredom - Do something different

When all of these run at the same time in a complex enviroment, you could get alot of emergent
behaviour. If you make the examples more domain spesifice, you will get cooler results.

The guys at MIT use this for their robots, and is very buildable and testable since you can turn
layers on and of, and test them individually and in pairs to see if they work as they are supposed to.

search Subsumption and Brooks for nice articles on the subject

Currently, I am experimenting with getting an agent to learn a goal-state and later return to that goal-state (See: NeuroLife). However I am working on a system that involves generalizing the agent's knowledge so I expect to see some emergent behaviour as the path to the goal-state becomes generalized. For example, if the agent has learned that stacking cubes increases the height of each cube and it has also been taught to use a ladder to reach an elevated position then I expect that the agent will attempt to use cubes to climb when there is no ladder available.

[Edited by - neuronz on August 24, 2006 7:34:04 PM]

How about Emergent behavure of the people playingt the game.

I was playing with the demo Deyja posted and developed a sort of hexagon bowling where you corall all but one hex in a corner then take the lone one out and wrap it up 3 or 4 times until it shoots out from the pressure, and getting it to hit and break up the formation in the corner.

or getting two or more hexagons to mate, wrapping several of them up untill they are jumbled together then all fly apart when the rope contracts

anyway just my thoughts