I forgot that we had RDF category indices too. There was lots of shonky stuff in there, including a non-existent "gs:" (oops, dated...) namespace for most of the stuff. So I worked it over too.
Before: http://london.openguides.org/index.cgi?action=index;index_type=category;inde...
After: http://un.earth.li/~earle/cgi-bin/wiki.cgi?action=index;format=rdf
(Examples selected for brevity of output - try using the W3C RDF validator to get diagrams of them.)
Again, in CVS on un.