Now, Searle asks us to suppose that he is sitting inside the computer. In other words, he is in a small room in which he receives Chinese characters, consults a rule book, and returns the Chinese characters that the rules dictate. Searle notes that he doesn't, of course, understand a word of Chinese. Furthermore, he argues that his lack of understanding goes to show that computers don't understand Chinese either, because they are in the same situation as he is. They are mindless manipulators of symbols, just as he is — and they don't understand what they're 'saying', just as he doesn't. Link
This is a good thought experiment to bring up when discussing how the mind is different from a computer.