I have a problem with some kind of Internet addiction. I want to block some sites on my Ubuntu 12.04 for myself. Changing DNS and /etc/hosts doesn't help couse I know pass and any time when I find myself frustrated I can chenge dns back and after that find myself searching through the stupid websites rather than work.

Is there any solution? Maybe some type of a programm where I need to enter a long password to change settings of Internet connetion. And this password will differ from my login pas which I always use. And I can stash this long pass far from me in a deep dark wood buried in a hole...