some time ago, I made an ad banner for SuperTuxKart.

Its code is very small:
HTML5:
- {l Code}: {l Select All Code}
<div id="stkAdBannerHTML5CSS3BySuperMat"><img src="http://supertuxkart.sourceforge.net/site/skins/stk/images/head/logo.png" width="100px" height="70px"><br>A kart racing game featuring Tux & friends<br><br><div class="ribbon"><a href="http://supertuxkart.net/Downloads" class="ribbon-fold">Download now!</a></div><br><br></div>
CSS3:
- {l Code}: {l Select All Code}
#stkAdBannerHTML5CSS3BySuperMat{width:200px;height:210px;background:linear-gradient(rgb(80, 80, 80), rgb(120, 120, 120));border-radius:10px;text-align:center;color:white;font-family:"Open Sans", "Helvetica Neue",Helvetica,Arial,Verdana,Geneva,sans-serif;z-index:-999;padding:1em;}#stkAdBannerHTML5CSS3BySuperMat #heading{font-weight:bold;font-size:20px;}.ribbon{width:262px;position:relative;background:rgba(200, 200, 0, 1);background-image:linear-gradient(45deg, rgba(0, 0, 0, 1) 25%, transparent 25%, transparent 50%, rgba(0, 0, 0, 1) 50%, rgba(0, 0, 0, 1) 75%, transparent 75%, transparent);margin:0px auto;z-index:1;left:-41px;padding:10px;color:white;}.ribbon .ribbon-fold:before, .ribbon .ribbon-fold:after{content:"";position:absolute;display:block;border-style:solid;border-color:slategray transparent transparent transparent;bottom:-25px;}.ribbon .ribbon-fold:before{left:0;border-width:25px 0 0 25px;}.ribbon .ribbon-fold:after{right:0;border-width:25px 25px 0 0;}.ribbon a{color:white;text-decoration:none;font-weight:bold;font-size:20px;}
It is released under CC-BY-SA 3.0.
If you want to support STK, you can add it to your Website, but maybe we should find a better slogan, Funto said it's pretentious.
Best regards,
SuperMAT
PS: It would be nice if you let me know that you use the banner.