Perhaps on all the wikipedias, there should be added in various languages,
$wgSiteNotice = '2007 Wikimania Taiwan...' /** If set, a bold ugly notice will show up at the top of every page. */
to drum up interest.
(Wikimania seems as important as the other things $wgSiteNotice has been used for in the past.)
P.S., http://wikimania2007.wikimedia.org/wiki/Team_and_Volunteers seems like it got vandalized.