New set of CAPTCHAs.[Old CAPTCHAs are here]
Multilingual CAPTCHA

Chess CAPTCHA

White's turn, present the best move for white in PGN format.

Pokémon CAPTCHA

A combination of which Pokémon types can result the greatest damage multipliers to the above 2 pokemon?

Divine CAPTCHA
Which 4 the following did not appear in the bible:
1. What will Jesus do?
2. Who will Jesus do?
3. Where will Jesus do?
4. When will Jesus do?
5. Give beer to those who are perishing, wine to those who are in anguish

reCAPTCHA uses the human intelligence to help the world of OCR. People solve not one, but two captchas, one is the one computer knows the answer to, the other one computer does not know. So answer only one is good enough if you know which one to answer. The other one will assume to be true if one of the captcha's result is correct.

It provide both visual and voice captcha. The voice captcha should only show the user the captcha the computer already knew, because it is not possible for computer to create voice out of a word it don't understand.

There is always a chance that a person got one of the word right the other one wrong, reCAPTCHA have a build in system just to prevent this. After a word is "known", the system will then show the word to other people to confirm if it's right or not.
I'm definitely using it soon :)

phpOCR is a class from Andrey Kucherenko that can do Optical Character Recognition. With a little training, the script's artificial intelligence can reconize more and more characters.
A application with the same name by Janis Putrams can be found at its sourceforge page.

Editor Comment:

Does this means PHP can solve CAPTCHAs too? I was browsing around for a OCR system because I was trying to capture result of some games.