I found WikkaWiki when I was searching for a solution for my company's internal need to implement a simple, fast and feature rich "CMS" system. Spending 2 hours opening up the source code, I FALL IN LOVE WITH WIKKAWIKI. The actions, formatters, and handlers concept was awesome. I don't know if this is original implemention of WikkaWiki or based on WakkaWiki, but still, this is something that I adore so much.
To further emphasize the beauty of Wikka, I am an ASP programmer, with little PHP experience, but I can understand the code almost instantly (ofcourse except for the RegEx :-), take me quite sometime to RTFM to found out what most code on wakka.php mean). I've created a test site on my server to play around with WikkaWiki. Feel free to visit and drop me some comments.
Wikka User's List
On your test site, you link the url http://wikka.jsnx.com with text WakkaWiki. Note that 2 are different, WikkaWIki is at http://wikka.jsnx.com and WakkaWiki is at http://wakkawiki.de. (I didn't correct it myself because I don't want my IP address to be shown on your site, since I'm not registered :)
What do you mean by emphasize the beauty? If it's about colors and fonts, there's just one single file you have to modify: wikka.css
What I mean is that the code of Wikka is so easy to understand, even for an unexperienced PHP programmer.