Dave Munger in his Cognitive Daily did an interesting experiment. He asked his readers to pick a number between 1 and 20. The "random" number picked by human is biased towards 17.
Is this culture specific? If you are interested to test it and if you are a blogger in languages other than English, please repeat Dave's experiment and tag your post with human-random-generator. If you can, please also leave a comment here so that other may follow to read your result.