ha lol... do u believe they are blocking urls (web adresses) or do u believe that they have an "Allow" list on the internet machine that only allows the sites added to work?
to test if its a url block go to google and type in "tom myspace" then click a few of the myspace links that pop up...if any of them work then its a url block and easy as hell to get around...if its an allow list then it might be a little difficult
also when u go to ur start menu can u go to network connections or is that blocked off?
feel free to experiment as most schools use a system called deep freeze and every change u make to the cmp gets un done when u restart the system
so in essece u could delete a couple operating system files which would normally screw a comp...but by restarting it the ocmp would be fine