>Honestly, finding a way to get fish from being blenderized in a car
>would be easier...  I looked into trying to build a wall-sized lava lamp
>  for shits and giggles once and it's decidedly non-trivial.  Contrary
>to conventional wisdom, there's no wax involved, but rather alcohol and
>a type of mineral oil.  Anyway, apparently all the firms have their
>special blends.  The two have to be in perfect balance and the
>temperature differentials have to be just right or you get mush.  Even
>the commercial ones can't be left on indefinitely and will ready a
>steady state after a number of hours.
>
>It's pretty fascinating stuff.  Check out this site form more details:
>
>  http://www.oozinggoo.com/howto.html

Also:
http://www.emanator.demon.co.uk/bigclive/lavalamp.htm