Jizao "Festival": the China Day for Kitchen God Worshipping
The day after, i.e. December 16th in solar calendar, will be 23rd of the 12th month in Chinese lunar calendar, one week before the New Year, which is Jizao Day in north China, and on 24th in south China. It is not a real festival, but a day for a very popular custom in public, i.e. kitchen god worshipping. Ji is a Chinese term for "sacrifice", and zao for "kitchen god".
In the first hereditary dynasty, Xia (2070 B.C.-1600 B.C.), there already arose the kitchen god in public legends. He currently became one of respectable gods in charge of ordinary life of public people. People regarded him with reverence and made sacrifice to him. In Shang dynasty about 3000 years ago, kitchen god worshipping has become a popular custom. Originally, ji was another word with the same pronunciation, which means to remember, i.e. ancient people made sacrifice to remember the foreman who taught them to eat cooked food. With time, the foreman became a god, and people would like to make sacrifice (i.e. ji) to him.
In ancient time, the ceremony of Jizao could be very severe. Every family member, wherever he was, he must have gone back to home for it. Step-children must have also attended, and after the ceremony they would have become one of official family members. According to public saying, the kitchen god returns to the Heaven on 23rd (and 24th in south China) to report to the Heaven Emperor about how common people behavior in the past year. Therefore, people put up the picture of the god (sometimes with his wife) in the kitchen, sacrificed offerings, and with serious ceremony sent the god back to the Heaven, hoping him to report about them with good words. Afterwards, especially in Song dynasty, the god became one with bad mouthing, because he is a reporter, or actually a snitch (I guess it must have been those bad people who initiated this because they were afraid). Then, people liked to sacrifice him a sticky sugar, which is called Jizao sugar, to make his tongue sweet or glue his lips together.
In recent time, Jizao Day was actually a difficult day for the poor, because landlords usually demanded them repayment of a loan on the day, which was called "the pass of the year". So, those poor people had to go out of the door to get through this, and came back until the New Year Eve, the day on which asking for repayment is a taboo, and so is in today.
Nowadays, old people and people living in farm areas still keep this custom, maybe not in that seriousness, but still have a picture of the god on the wall in the kitchen, and lay out some common sacrifice food, like Jizao sugar and Jizao soup, in front of him. Usually, people clean their kitchens completely this day, probably play fireworks and eat dumplings. The Day is also called "pre-New Year". From this day, people begin to prepare the New Year.