if your school has any macs running os 9.2 (no matter how much of a user restriction) there is always a way to launch the browser. (if you have photoshop, say in the art department, then just click the "adobe online" button and it will launch it) from there, if you type in a url but then stop it before the message comes up saying access denied and then change your IP address. and press refresh it will load the page(works only once and then you have to change the ip again)

this will work most of the time unless they restricted the browser specifically. (usually not the case)

Good luck, and you can always try a proxy server.

(This information brought to you from hours of testing during a digital arts class)