Alright, I have checked most of the topics about web filter circumvention, but FortiGuard blocks all of their solutions. The system includes some sort of way to determine any new proxy-I'd imagine before loading the site, it pings to see if the site loads a test flash, which leads to them calling it a proxy. Here is the site:
http://www.fortinet.com/products/web_filtering.html and here is a utility that checks sites versus the database:
http://www.fortiguardcenter.com/webfiltering/webfiltering2.html . If you have a suggestion, please make it browser-based because the teachers really do not care if you screw around in IE, but, in the non-browser world, for example, my friend got detention for toggling the brightness.