Magic sand 
Magic Sand, also known as Space Sand or Aqua Sand, is a hydrophobic substance. It's basically small bits of silicon coated with a water resistant compound.
You can pour this stuff directly into water, remove it, and it will keep dry, as if the water never touched it. As the water wraps around the sand, it creates a thin space between the two substances and the reflective surface of the water gives off a beautiful shimmer, similar to silver. It is really fun to play with and very attractive to look at.
You can get relatively small quantities for just a few bucks at online science/hobby shops.
Wikipedia:
http://en.wikipedia.org/wiki/Magic_sandFeb 17th 2011 