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.

tibouille

This plugin allows you to include sudoku puzzles in your blogs with a simple shortcode. The sudoku puzzles can be inserted everywhere: in your theme files, posts and pages.
Parameters:
<ul>
<li>Size of the sudoku puzzle: 9×9, 10×10, 12×12, 16×16.</li>
<li>Difficulty level: easy, medium, hard, expert.</li>
<li>Width (and height) in pixels (not less than 450 px).</li>
<li>Background color.</li>
<li>Available in english and french.</li>
</ul>
For more details and examples visit the plugin page on <a href="http://www.live-sudoku.com/site-perso/wordpress" rel="nofollow ugc">live sudoku</a> or on <a href="http://www.le-sudoku.fr/site-perso/wordpress" rel="nofollow ugc">Le sudoku</a> if you speak french.
<h3>How to use</h3>
Visit <a href="http://www.live-sudoku.com/site-perso/wordpress" rel="nofollow ugc">sudoku in your WordPress blog</a> or if you speak french <a href="http://www.le-sudoku.fr/site-perso/wordpress" rel="nofollow ugc">sudoku sur votre blog WordPress</a>. 
You can also check out the source repositories on <a href="https://bitbucket.org/lesudoku/sudoku" rel="nofollow ugc">bitbucket</a> or <a href="https://github.com/sudoku/sudoku" rel="nofollow ugc">github</a>.

Sudoku Shortcode

Fast and easy integration of sudoku puzzles into your blogs, with some parameters.

Captcha Garb vs Sudoku Shortcode