Lots of people are demanding more proxy sites because many have already been banned by their school or workplace. It´s not easy to find new ones but maybe the list from econsulting might help you. They have a list of 250 web proxies that might not be banned. I think it´s worth a try if you are that desperate.
Another method would still be to setup your own proxy server, which means more work but a good chance that you are able to surf your beloved sites again. You could also try and setup a normal http proxy in your browsers settings if those are not disabled from your systems administrator.

Proxy Sites
Free online web proxy
Automatic Web Proxy Server In Firefox
it i s banned
Hey,
I’ve just setup a new list of web proxies, you might want to check out: http://webproxies.info Each proxy is tested everyday, you also get a screenshot and location of the proxy.
Let me know if you find it useful!
Help me . i vanna proxy.plz
this site is fucking gay…..none of your shit works ………FUCK YOU!
http://www.google.com/gwt/n
isnt blocked yet
try that
Dear , we have a firewall, this firewall feeling PROXY word and ur all proxy sites have proxy word , or in like or in page
and i can not use from anyone of ur proxy list
:((
Yup, nothing on this site works…no even with the low-level security we have in the Northern Ireland UBI campuses. Maybe you should get a job or something….or stop posting un-reliable proxy sites.
um. I am at school and none of these sites work. I really wanna get on myspace. Help/.
None work :/ need a new proxy site…..
Well, there isn’t much you can do about the school proxy sites because they are managed at whatever central office in your county manages them. Sorry guys, bring a laptop with wireless interent or deal. They have cracked down on my school too, fuckin pricks, lol.
need proxy