"A novel way to tell if you are a human ;)" -- Maciej "mav" Trębacz
This is a php library which allows you to include a fun and simple captcha in any of your html forms.
The library is a fork of Maciej's original library hosted at google code which has been inactive for quite some time. It also features cute and colourful animal images made by Martin Bérubé.
The minimal requirements is that you have php running on a webserver and if you want random image effects to be applied to the captcha images (to make sure they are different everytime) you will also need either gd or imagemagick installed on your server.
Please see example.php in the repository for a basic example of how to use the library.