I saw a comic at some point where a robot was getting a captcha tattoo, completely unaware of it's meaning. You know, along the lines of the joke that people getting those chinese character tattoos wouldn't be able to tell "power" or "tranquility" from "floozy" or "horse's ass".
I did manage to fail a captcha today. One character threw me; it was sort of like it could have been either a zero, an O, or a 6, but it's loop wasn't closed. The next one I got had a # and an % in it, so maybe it was a @ without the lowercase a portion in it. In any case, I'm totally not a robot, bleep bloop.