If not just the local country's programming contests i've mentioned earlier, but i also participated in Google's unofficial "Ants" AI contest with pascal, when it was still in beta. Site seems to be up still http://aichallenge.org/
All these contests use console writeln/readln style. Google's Ants is specially different from other ones i did, in that there can be as many as 8 AI's playing in the same game. The game hoster does some automatically simulated games every now and then, and then posts statistics. But i'm not asking anyone to do competition as complicated as that Much less features still can make a good contest.