Game Captcha is a different, funny and interesting style you can use for stopping spams coming to your WordPress site. FunCaptcha – game CAPTCHA is a free WordPress plugin which is also compatible with BuddyPress & Contact Form 7 and even it works very nicely on every desktop, all browsers and mobile device systems.
Generally WordPress website owners use CAPTCHA plugins for protecting their site from Spam Bots. This tutorial explains you working of a free WordPress plugin you can use for protecting your WordPress installation from Spam Bots without installing any type of captcha plugin. Keypic.Com is an online service that provides you with free plugins now only for WordPress but for other Opensource blogging platforms like Drupal and next month (as scheduled) they would be launching plugins for Joomla, php. More plugins would be available in the near future for MediaWiki, Typo3, vBulletin. For more information on plugins visit here.
Captcha Grab is the new stylish comment spam blocker that makes your visitor solve the puzzle images. It includes 58 puzzle images that get displayed randomly and you can upload your own.