Between 2003-2005 I often used Swi-Prolog for semantic web experiments before I more or less settled on using Sesame (and occasionally AllegroGraph and Redland).

I just saw a link to the ClioPatria semantic search web-server project. Assuming that you have a fairly recent copy of Swi-Prolog installed, trying ClioPatria only takes a few minutes:

git clone git://eculture.cs.vu.nl/home/git/eculture/ClioPatria.git
cd ClioPatria/project-iswc
./configure
/run.pl

Then, point your browser to http://localhost:3020/, load, for example, a OWL (XML format) data file, and try some queries. The default query language is SeRQL which I don’t use, so I set the query language to SPARQL and all seems to work fine.

One good thing about Swi-Prolog and the bundled SemWeb library is that loading RDF data and performing queries seems very quick compared to Sesame which is what I usually use. As a result, the ClioPatria web application is also very quick.