webgarb

Captcha Garb is yet a stylish puzzle like fun comment spam blocking plugin that block spam comment posted by automated bots.
The plug-in comes with 58 cool puzzle images and you even can upload yours direct from captcha garb admin page ! :).
Please comment you view about this plugin here <a href="http://webgarb.com/captcha-garb/" rel="nofollow ugc">Captcha Garb Page</a>.

Captcha Garb

Fun Captcha that your visitor also like to challange it.

Jacob N. Breetvelt

This plugin can display a sudoku puzzle diagram on your website. 
It comes with 200.000 unique puzzles in 7 different levels of difficulty. 
The number of times a puzzle is successfully solved or failed is registered. 
There is simple help and statistics available at the front-end.

WP Sudoku Plus

This plugin displays a sudoku puzzle diagram on your website that the visitor can try to solve.

Captcha Garb vs WP Sudoku Plus