DNJ Dilemma, the upgraded version of my Dilemma game, is online at Developer Network Journal's website. You can watch computer strategies play against each other, and even write your own - DNJ Dilemma is designed to accept extra strategy functions, and its help pages contain full instructions for writing and implementing them.

To play the full version of DNJ Dilemma, visit http://www.dnjonline.com/dnjdilemma/index.htm.  

OK, now back to the old version...

Dilemma (or Prisoner's Dilemma, to give it its full title) is one of the simplest games ever invented, yet generates some of the most complex interactions between its players. I first came across it in  The Selfish Gene, Richard Dawkins' book about the way our genes influence our behaviour in order to optimise their chances of replication. In  the chapter entitled 'Nice Guys Finish First', the author describes how cooperating with others can bring the best rewards for everyone, but only if no-one tries to make a fast buck by cheating. That choice - to play fair or double-cross your fellows - is what Prisoner's Dilemma is all about.

In this version of the game you play against the computer, which has four built-in game strategies. It's easy to play, and you can get instructions and tips by pressing the Help button.