Wie geil is das denn?

sorry but I had to write that in German… it means sth like WTF?!
The internet is really great… you can find everything… things you would have never thought about… like this:
I found the link on a german Newspage (heise online):

here we go http://www.carstuckgirls.com/!

If someone could explain that to me, please!
btw it was awarded for a Webby Award