Why aren't Site Templates working? What am I doing wrong?!?

I'm trying to create a few public facing pages. I believe I have sites set up correctly, but I cannot, for the life of me, figure out how to get rid of all the Salesforce stuff on a page and use my own template. I've read the docs over and over, modified the default SiteTemplate, edited the SiteHeader custom component, and nothing ever changes!

Please see http://frog.force.com/helloworld to see what I'm talking about. I just want this to say, "Congratulations..." on a blank, white page (no header, no footer, nothing, just the content of the visualforce page).

What am I missing here? I've fiddled around with every option I can find, and nothing will change the layout. :(