Calendar icon Captcha My Calendar icon seems to have changed to something that looks like a Captcha prompt. What goes? Can I make it something recognisable by a human being?
Have you tried restarting the dock?
Restarting the computer? 

It looks like the icon got corrupted.

My caveat is "When in doubt, cycle power".

If cycling power does not fix it you may try disk utilities>repair disk.

After that you may have to restore iCal from a time machine backup or reinstall iCal.