Simple captcha image generator gem

Solve Media CAPTCHA Replacement

A captcha that uses images instead of garbled text

This plugin adds helpers for the YinXiangMa CAPTCHA API

Simple captcha

Helps humankind with simpler captchas

Form protection with simple captcha calculations.

A honeypot style captcha extension for ActiveRecord. Simple one-line inclusion in the model combined with a simple form field should trap the bad guys in the molasses.