This is absolutely hilarious — the Geocities-izer. Hilarious because I was there designing pages like this back then. Go to this website and enter the URL for your own website (or any). When you click submit, you’ll see (and hear!) your site “like something created by a 13 year old in 1996” (as the WinXP newsletter describes it; thanks for the link guys).
Don’t worry, it’s not a permanent change to the site. But if you link from the 1996-ized site, the next site will be 1996ized too. You have to close the window/tab to cancel the process. What’s even more fun is that if you then open a new window and go and do it again, you get a different 1996 design entirely.
Here’s an image of THIS site a-la-1996: