From what I've heard, gandhari was married to a goat to avert a calamity before marrying Dhritarashtra. When Dhritarashtra came to know of this he imprisoned the entire gandhar clan. In prison, they were served just one fistful of rice every day. Realizing that this was an elaborate plan to starve them to death, Gandhari’s father declared that none but his youngest son would eat the sparse food being served, so that at least one amongst them would survive to avenge the death of the rest. The youngest son of king Subala was Shakuni. He survived and swore not to rest until all of Kuru kingdom is destroyed . He used the bones of his father to make the dice with which he was able to defeat the Pandavas in the gambling match, and thus which eventually led to the war at Kurukshetra and also to the destruction of entire Kuru clan.His father twisted his one leg to give him a permanent limp as a constant reminder of revenge. Guess the dice used by shakuni was made of his father's ashes......