“The Firefox add-on China Channel offers internet user outside China to surf the web as if they were in China. Take an unforgetable virtual trip to China and experience the technical expertise of the Chinese Ministry of Information Industry (supported by western companies). It’s open source, free and easy.”
The add-on was developed by Aram Bartholl, Even Roth, and Tobias Leingruber. Basically, it’s based on the SwitchProxy Tool add-on, which allows the browser to connect to various Internet proxies inside China. Thus, the user gets a Chinese IP and therefore is the subject of the Chinese censorship
The add-on is here. Simply install it and then try to search for dirty words like democracy, freedom and Tiananmen square. The authors guarantee that they have been mopped out of the web by the Chinese censorship. However, they don’t guarantee you being taken in custody by the Chinese police for searching for such words. I guess every piece of software has its flaws.