On this site you can find links to experiments in reasoning, language and music.
In this webexperiment you can evaluate how well you can predict the next letter of an unknown English sentence. The first letter is hardest, but soon it will get easier. The best possible score, scientists think, is around 1.1 (the lower the better), but it will be hard to score better than 1.5. Good luck! (Based on a famous experiment by Claude Shannon from 1961)
How predictable are you?
Are you capable of total randomness? Or is your behavior always guided by some rule? Here you can find out whether you can fool a computer, or whether the program -- "Shannon's mindreader" -- can predict your next move.