I just saw this on Metafilter and I know am I in trouble. It is riddle game that is embdeded in html. So basicly you have to figure out what the next level URL is by looking at the clues hidden in the page.

So far I have reached level 10, but thats cause in finding level 5, I found level 10. I will deal with it later when I am at home.

Good Luck.