A square unglazed 'quarry tile' available at various home improvement
places, tile purveyors, flooring companies and so on, makes a fine pizza
stone.  Don't forget the polenta (coarse corn meal) to sprinkle on the stone
to prevent any pizza epoxy deposits.  You can heat the pizza stone/ quarry
tile in a pyromid.  The square quarry tile also works as a reg'lar baking
stone of course.  Muffings, cathead biscuits, cornbread in cast iron... the
opportunities are limited only by your imagination.

Word of caution, do not WASH the stone.  Unglazed as it is it can absorb
enough water than when heated it can a poor imitation of an IED and self
destruct.  Just scrape it off occasionally or replace it when it's deemed
unsuitable.

Heat the stone first, using your IR thermometer purchased at RatShack, the
one you use to find hotspots in your radiator, to check the temperature,
then put on polenta and the pizza.