Remote to your home PC (RDP,VNC,log me in etc) and do whatever you like.
www.logmein.com install on your home pc then log onto the website to control your computer.
It depends what sort of proxy they use, google for a proxy anonymizer, if they are using ISA server to block by name, then get the ip address for the site you want and then type that into your browser instead. Works for me.
All well and good on a badly configured ISA server, but if it's set up properly it won't allow browsing directly to an IP address anyway.
Indeed, some people dont know how to set them up properly hehe