The majority Han Chinese have long followed the tradition of eating laba rice porridge on the eighth day of the twelfth lunar month. The date usually falls in min-January and is a traditional Chinese festival.
Legend about the origin of this festivity abounds One maintains that over 3,000 years ago sacrificial rites were held in the twelfth lunar month when people offered up their prey to the gods of heaven and earth. The Chinese characters for the hunt and the twelfth month (lie and la) were interchangeable then, and ever since la has been used to refer to both. Since the festival was held on the eighth day of the last month, people later appended the number eighth (ba in Chinese), giving us the current laba.
本文来源：http://www.010zaixian.com/zuowen/labajie/1050641.htm