I want to customize the way that Special:Randompage works on a
MediaWiki installation.  Is it possible to edit the way that it works
to search only a subset of the pages in a namespace?  I'd like to have
it exclude articles that are in only one of certain categories.  For
example, if there are a bunch of pages in Category:People, I don't
want those to be part of the "random search" unless they are also part
of another category.