One Pocket is a very popular pool game among gamblers and professionals. In America the game is now played even more than Straight Pool (which at one time was the only game played by the pros).
The following is a simple description of the game:
Each player chooses one of the two corner pockets at the foot of the table. Whoever makes eight balls in their pocket first wins. If you make a ball in your pocket and one in your opponent's, you each get credit for a ball. If you make a ball in an unassigned pocket, it gets spotted either when you miss or when there are no other balls left on the table. If you foul, you spot any ball made on the shot plus a penalty ball. If you make a ball in your opponent's pocket and scratch, it does not count for him, but is spotted along with a penalty ball. You only shoot again if you make a ball in your own pocket.
The game is well liked among gamblers because it can be easily handicapped, e.g. a good player may be required to make 10 balls before the lesser player makes 6.
The game is also called One Hole by those in the know.