Thach Khoan temple festival, held on 24 and 25 in January (lunar calendar) is the festival of Muong People in Thanh Son, Phu Tho. The Thach Khoan temple festival attaches to the unique ancient temple of Muong people in Phu Tho province where worshipping the god Tan Vien Son under Hung Kinh dynasty, three princesses of Hung Kinh and 4 head of the tribe of Dinh family, Muong people who have the credits to help Le king for fighting against Minh enemy in the 15th century.
Before the festival day, the organization board selects 22 kind-hearted old people, virtuous and gentle people, united family to arrange to the mandarins to sacrifice. The writing of the funeral oration is an important work. The content of the funeral oration requesting for prosperous country and peaceful people, timely rains and favorable weather, abundant crops, happiness for people. After the sacrifice, they burned the funeral oration and the next year, rewrite it. During the festival, many folk games full of national characters are taken place. In which, the game of throwing a ball through circle attracts most of people to participate in, which is a chance to open the exchanges, making friends and showing love.