Arduino / Xbee network

I will be running some workshops on the Creative Computing course at Bath Spa in January with kit supplied by Farnell Element14. I want the students to create a network of nodes that communicate with each other and have some element of generative algorithm to them. I have built a proof of concept as seen in the video, a single node generates an audio and LED output and sends the message to another node, that node displays the incoming message and then generates one of its own to signal another unit. Right now everything is generated pretty randomly and the nodes choose another one to send their message to at random. Things will get more interesting when we link colour and audio frequency and think of more interesting ways to generate our message. Perhaps some nodes will favour talking to others or malcontents will start interrupting the current conversation? I am interested to see what behaviour might emerge when there are 10 of these things going and each has its own 'personality'...