is an interesting experiment in user interface.

Throughout the entire web site you won't find any buttons or other items that you'll need to click on. Instead you navigate using several different methods of moving your mouse over interface elements.

Once you play around there a bit you start to get the hang of it and learn more about the different concepts that are demonstrated there.

BTW: so you forget that you aren't supposed to click then every time you accidentally do click on something you get a "subtle" reminder that you shouldn't.