The Chinese Twitter equivalent Weibo censors searches for the names of places where there are protests (currently Shenzhen). You could write a script that searches for the main Chinese cities on Weibo and plots the ones that are censored on a map. Presto, a dynamic map of Chinese political unrest! With data supplied by the Chinese government, no less. Who will do it first?
Update same day: Daniel Becking points to the highly informative web site Blocked On Weibo. It has a wide remit. The most recent entry explains why the two characters for “pantyhose” are blocked.