How do I do news, events and forum pages on mediawiki?
That a rather unspecific request.
Not sure about news - do you want to aggregate RSS feeds from news sites like CNN.com or BBC.co.uk? Or do you want something like WikiNews.
For events, the Calendar extension could be useful: http://www.mediawiki.org/wiki/Extension:Calendar_%28Cdamian%29 Also see the recent thread(s) on this issue.
As for forums, there is AWC's Forum Extension: http://forums.anotherwebcom.com/vb/wiki.php?page=Category:MediaWiki:Forum Not having used that myself, I'm not sure whether it works with the latest MW version (though I believe Wikia uses it).
HTH.
-- F.