Plugins - CAPTCHA
Add to favoritesValidate the humanity of your visitors with either the common text rendered in an image or a simple question.
The image part requires RMagick and eyes (that work).
Note: I've changed the URL for the repository. The old one will still work but will not be updated.
http://sargon.interinter.net/validates_captcha/
http://nimrod.interinter.net/plugins/trunk/validates_captcha/
Rails' (MIT)
Model
Nice plugin