30 selfish prisoners having sex and mutating. WHOA.
very basic evolutionary algorithm, a last night's play.

a problem:

Will the two prisoners cooperate to minimize total loss of liberty, or will one of them,
trusting the other to cooperate, betray him so as to go free?

In the iterated prisoner's dilemma the game is played repeatedly.
Thus each player has an opportunity to "punish" the other player for previous non-cooperative play. 
Cooperation may then arise as an equilibrium outcome.

solutions:

"morality" evolved, but I didn't get tit for tat wich I originaly expected,
(or any long-term stable strategy) A cooperating species evolves out of an uncooperating environment,
and all is nice until an evil mutated agent is born. an agent that successfily exploits the current
dominant species. a parasite quickly spreads and kills off the whole species and itself.
I haven't explored it in detail yet.

I'll post more info and code later or never.
screenshot and someone with different and more serious? approach.