See also CSS reference guide and examples
Takes an image and produces a small reflection of it underneath. It actually looks nothing like the image here as it's a reflection and not a gray shadow, but it's late and I can't be buggered finding a proper icon to go here and you get the point.
Tool bars and other bars.
Make box graphic elements.
Multi column HTML page layouts, and fancier.
Make graphics out of text.
Adding text to a picture.
"page loading" spinning (Ajax) icons.
Really things you'd play with for fun rather than use as a tool of some sort. And they are fun.