Rich Points at Community Cycles (Boulder, CO, USA) has complete control of the bikecollectives.org and bikebike.org domain names and hosting.  However, the wiki has been under serious attacks from spammers (http://www.bikecollectives.org/wiki/index.php?title=Special:RecentChanges&limit=500), so he needs your help to come up with solutions.  Specifically?

We need a MediaWiki security solution that still keeps the wiki easy to contribute, but keeps most of the spammers at bay and doesn't burn out the moderators.  So far we have implemented ReCaptcha and email validation requirements on user creation, but it appears even those are being thwarted.