Nice game, BUT. The Mac version caused me some pain. I chose the default fullscreen settings, and I couldn't quit the application for minutes. No quit button that I could find. No drop-down menu bar. Cmd-tab stopped working. Mission Control (F3) stopped working. WTF? Finally I figured out that alt-cmd-esc still works, and then I could quit the game.
Hey rationality friends, I just made this FAQ for the credence calibration game. So if you have people you'd like to introduce to it --- for example, to get them used to thinking of belief strengths as probabilities --- now is a good time :)