Many schools, collages and offices blocks social networking sites like Orkut, Facebook etc. There is a very simple way to open these sites. Use a web proxy and you have done it. Proxy servers hides your privacy and network administrator will not detect what are you doing. Anonymous free web proxies allow you to bypass local proxies and security restrictions and surf blocked sites or simply surf privately and securely without need to install any software on your computer. If you browse the web through public web proxy the website cannot find your real IP address. You IP address gives out information regarding your location, OS, web browser, etc which can be misused.
Just look for a box like image shown right side on the site. Enter the website you want to browse and click Surf and you have done it. Social networking sites may ask for verification, it depends upon your social networking sites.
List of Working Proxy Websites collected through internet
Let me know if any web proxy site is not working, i will update new list.