I've made a captcha extension. Besides Math Question, I added several new challenges.

You can have it, but don't forget to drop me a comment/critic Please note that this is only compatible with Drupal 4.7

INSTALLATION
To install the module, you have to have an active captcha module on your drupal. Next, just copy arnoldcaptcha.module to dir modules. Afterthat, activate the module (arnoldcaptcha). Go to administer-settings-arnoldcaptcha, choose what kind of challenge which will be activated. Lastly, go to administer-settings-captcha, and change captcha type to arnoldcaptcha.

EULA (END USER LICENSE AGREEMENT)
Use this at your own risk. In other words, I don't responsible for any damage done by installing as well as using this module. This is an open source module so feel free to modify and redistribute the module however you are obligated to include my name and website in your source code. By downloading the module, you have agreed this agreement.