I Served Serial Joe a Slushie

Wow, this is really smart. For those without the patient to read the article, there was a new winner in the annual prisoner's dilemma competition. I had read somewhere that it was "proven" that the tit-for-tat strategy was optimal. But these people from Southampton came up with a really smart idea. See, there's no limit on how many programs you can submit to the competition. So they submitted 60 programs. The program had a series of opening moves, by which it could recognize whether it was competing against another Southampton program. If it did, the two would work together, by having one always co-operate and one always defect, resulting in the one scoring very well, and the other scoring badly. If it wasn't playing against a Southampton program, it would never co-operate, to ensure the enemy program didn't score very well.

They ended up with the top three winners, and (naturally) lots of programs at the bottom :) Brilliant!