People try to open these blocked websites but they get failed because they don't know the right path of opening a blocked website. Most firewalls block almost all type of proxy websites through which you can access the web. However if you join any proxy group on yahoo or google, they send new proxy lists in your email that helps you to see blocked websites.
Here are these small size software's that will help you out. Download it from somewhere and use it on your workplace. You can take these soft in pendrive. There is no need to install them. They run directly.
3. Puff the Magic Dragon
Another thing you can do is to translate the web page. By translating the web page the firewalls do not block the web page and you can surf the whole website easily. Use Yahoo babelfish and googel translator.
I hope it will help you a bit in unblocking websites.