Say this posted today on lounge forums on CodeProject:

http://andyslife.org/games/sand.php

Simply select your material from the list below and then drag around the screen.  For example, select “Wax” and then drag it around.  After it collects some stuff, then place some fire under the wax.  Yep, it melts :)

Warning, be sure you do not have any deadlines before entering the site :)