Hey how would I go about disabling internet on Ubuntu 12.04? What I want to do is keep the computer connected to the wireless network, but I also want it to be unable to access or be accessed by the internet when it is still connected. How would I go about doing this?

I have thought of maybe messing around with the hosts file, but I really don't want to break it permanently because i have never really touched that before.

Any and all suggestions would be most appreciated.