Simple Captcha : Zero Dependecy Captcha for Rails

Finally after long wait, the next stable release of the fun-du, simple
and useful plugin SimpleCaptcha is here!.

Major changes have been incorporated to the plugin in this release
1.2.0

Which includes…

* No Pre-Requisites
* RMagick NOT required anymore
* FileSystem Usage Removed
* No third part dependency(NO API call!)
* Works Perfectly with Multiple Clustered Servers
* A completely local application based ZERO DEPENDENCY CAPTCHA

And many more…
Read here( http://expressica.com/simple_captcha ) for implementation,
usage and examples.