The latest issue of Scientific American has an article: Christof Koch and Giulio Tononi (you need to access the issue to see the full-text. The website just provides you an introduction to the article). It is very interesting. If I have time this summer, I will attend the competition. In fact, I have several ideas to cheat their smart computer. But I don't want to say much right now. However, I'd to say, the picture that the authors provide (see below) is easily recognized by computer algorithms as a unreasonable picture. Their algorithm just needs to do object recognization and then do some semantic reasoning, then it can know this picture is not reasonable. So, don't be misled by the authors' picture.
(The picture's credit to Scientific American)