I've been using FlexWiki for quite a while now, I'm assured, that in many aspects this is the best wiki around. I'm running separate FWs for several projects I'm involved in (I won't link them, beacause they are not publicly accessible.)
My favorite part is WikiTalk, I'm a script enthusiastic...
Altough I've very little spare time, I'd like to contribute to this community, beacuse I've already recived so much.