This weekend's FT has a wonderful article which traces the history and idiosyncrasies of the Hong Kong dim sum ritual. The term 'dim sum' (which are the dumplings and other small eats served in a teahouse ritual) comes from the Cantonese dialect form of the Mandarin 'dian xin'. It is a curious term that defies direct English translation, but means something like "touch the heart". Its origin dates back to the Song Dynasty (AD960-1279) where historical sources mention it as a name for the snacks customarily served for breakfast.
Another interesting thing about a dim sum breakfast, that we foreigners don't probably notice much, is the fact that it has its own particular little table mannerisms. Like you may thank your host for pouring tea into your cup by tapping your index and middle fingers lightly on the table.
This practice is said to date back to the 18th century, when Emperor Quinlong went on a fact-finding mission to the south of China. The actual story goes like this:
"Travelling incognito, as emperors sometimes did in those days, in an attempt to understand what was really going on in China, he dropped in on a teahouse with his small retinue. When the emperor poured them some tea, his footmen were flustered because palace etiquette dictated that they knew they should not give away his disguise. So they tapped their two fingers on the table as a miniature form of prostration, laying the foundations of a habit still common in Cantonese communities all over the world."