Online computer programming competitions in the Java, C++, and C# languages. Competitions take place twice a week, and members can win from $25-$300. Major tournaments have a prize purse of $250,000. http://www.topcoder.com/
A unique annual contest in which a winner is selected from participants who comes to the closest to demonstrating that machines can think like humans, as per the Turing Test. http://www.loebner.net/Prizef/loebner-prize.html
If you are preparing for a programming contest, this page might be useful. Includes past problems of national, regional and international contests. http://www.inf.bme.hu/contests/tasks/