Some time ago I tried to install MediaWiki here. But as my hoster Comball does not have PHP 5 on their servers, MediaWiki did not work.
The other day a friend has been using a wiki, that was the same that is also used for the Web Montag web site: DokuWiki. So today I downloaded it, put it on the server and only some configuration later it was running. So here it is: portenkirchner.net | Wiki.