Many CMS' have news on the front page, where e.g. the sysop/webmaster posts about down time and other important news.
Often these can be scheduled, so that you e.g. write on Monday, and wants it to be visible from Tuesday to Friday.
Question
Does MediaWiki have something like that?
Yes, you can use the #switch function to do this. There are some examples on this article - generating dynamic content with mediawiki.
The documentation on #switch is here: http://www.mediawiki.org/wiki/Help:Extension:ParserFunctions#.23switch
The "dpl" (Dynamic Page List) extension can also be used for that.
We use the following to display a random page from our site on our landing page. With DPL, you can filter that to a specific category, or filter by myriad other means.
<dpl> namespace= includepage=* includemaxlength=600 escapelinks=false resultsheader=__NOTOC__ __NOEDITSECTION__ randomcount=1 mode=userformat addpagecounter=true listseparators=<h2>A Random Selection From Page: , [[%PAGE%]]</h2>,,\n\n </dpl> 