Acronym for Double-Or-Nothing type of Sit-n-Go tournament. The tounament ends once half the playing field is left, awarding the surviving players double their buy-in. DON strategy differs from normal Sit-n-Go strategy since you are not playing to win the tournament, but rather just finish in the top half of the field.
Example: I played a $10 10-Player DON at PokerStars. After the 6th player busted out, I doubled my money to $20.