I was thinking of possible demo projects for an RoR training that I'm coordinating for a team of 5 people... my mind wandered off to implementing something like an online version of an information radiator... of course that in itself is a falacy as it is almost mandated that an IR should be offline, a physical whiteboard or wall poster!
Anyways, some good links to read up on IRs:
http://www.ayeconference.com/wiki/scribble.cgi?read=InformationRadiator
http://www.lunatech.com/archives/2005/10/07/information-radiators
http://www.agileadvice.com/archives/2005/05/information rad.html