WakkaWiki - a new PHP Wiki
"Wakka is a Wiki-esque website toolkit written in PHP. It's small, light-weight, somewhat fast-ish, and easily extensible through plugins that are essentially PHP includes. Great care has been taken to ensure Wakka can either easily integrate other applications or vice versa." And in a first impression, I like WakkaWiki much better than PHPWiki. Could become my Wiki tool of choice pretty soon.