Interesting site for checking out your browser history.

http://startpanic.com/

Does nothing malicious. It will will show you sites you've been to with that browser.

**disclaimer**
Don't blame me if your parents find you've been on 4chan and porn sites with this. :]


PS- Its a cheap method to find the list of visited sites (they have a database of 100,000 sites they look up with client side javascript)

PPS- Doesn't post details back to the site, but modifying the code wouldn't be difficult.