We are currently using prep/ibiza from http://perl.pages.de for our old-fashioned websites and Mediawiki-syntax for about.psyc.eu.
This site started out as a wiki, then turned into a large website with Mediawiki as its CMS. Happens frequently I guess. So the old websites may end up getting integrated into this one.
As PSYC moves on we are risking of getting spontaneous public attention anytime, but the way this Mediawiki is set up would not stand such a load. Progress is underway to make it more load resistant. Current status: We now have the ability to keep a static copy of each page as it is created, so we could at least direct non-editing operations to a static web server. So far the static versions however look very ugly, so this isn't in active use yet.