Zhou Youguang is 106 years old and became active in Chinese politics only in his late 80s, according to an International Herald Tribune article published earlier this year (and sent to me by a friend - thanks, Elizabeth). He is perhaps best known, and most celebrated within China, for inventing the Pinyin system, which is a Romanised spelling system for Chinese characters. Pinyin literally means 'to piece together sounds'.
Children in Britain may learn to read and write using the phonics method, where the sounds of words are pronounced individually -- C-A-T (Kuh-Ah-Tuh), for instance. However, this system doesn't work for a language without an alphabet, like Chinese, and Zhou was entrusted with the task of inventing a phonetic alphabet in order to help more Chinese people become literate. It did have a huge effect on literacy in the country. The article mentioned above says that nowadays all Chinese pupils begin with Pinyin before moving on to characters.
Creating the Pinyin system was a mammoth job, the first task of which was to decide whether to use an existing alphabet, such as a Cyrillic, Japanese or Roman alphabet, or whether to invent a new Chinese alphabet. Zhou felt that using a Roman alphabet would help China connect better with the rest of the world.
Zhou had an interesting, if difficult at times, life, working in a Wall Street bank (he was an economist by profession with an interest in linguistics), having several discussions with Albert Einstein and being in and out of favour with various Chinese governments, with the result that he was banished to a rural wilderness for two years to undergo 're-education'. Here's the full article.