Ive seen tunneling working many times but i have sadly never come to setting it up myself , The trick is to set up two PC's.
One at school and one at home. These PC's communicate over port 80 by using an custom protocol like ssh (or an web based ssl protocol). This then allows you to set up your own proxy from the ouside
Scheme
-school side
pc with ssh client over port 80
-Home
pc with ssh server on port 80
You log in on the home pc and use lynx for example to browse.
I agree this is some kind of fake tunneling method.
But this is an real tunneling method
http://www.dbovernet.com/httptunnel.htm
so maybe this is usefull.