Pig (dice)

Pig is a jeopardy (risk) dice game played with one die. In jeopardy dice games, a player decides to "roll" or "hold" (stop rolling). A player that rolls risks a turn total, and may gain a higher turn total or score nothing. A player that holds scores the turn total.
John Scarne wrote about Pig as a common dice game in 1945. Optimal (perfect) play has been computed. 
Teachers often use Pig for fun lessons.
Rules.
On a player's turn, a player can roll or hold:
The first player to score 100 or more points wins.
Example Play.
For example, Ann begins a turn with a roll of 5. She could hold and score 5 points, but she decides to roll again. Next, Ann rolls a 2. She could hold with a turn total of 7 points (2 + 5 = 7), but she decides to roll again. Next, Ann rolls a 1 ("pig"). She must end her turn. Her score does not change. She hands the dice to the next player, Bob.
Bob rolls a 4, 5, 3, 5, and 5. He then decides to hold. Bob adds 4 + 5 + 3 + 5 + 5 = 22 points to his score.