From wiki.network-crawler.de

Change the navigation menu

You only have to change the contends of (within your wiki of course):

MediaWiki:Sidebar

Change the toolbox items

The toolbox is a dynamic element and cannot be easily customized. Copy skins/MonoBook.php, creating a new skin. Then go on hacking it!

Block users - due to spamer!

http://meta.wikimedia.org/wiki/Preventing_Access