In cricket, a "leg bye" is a type of extra, a run scored by the batting team without the batsman hitting the ball.
If the ball strikes a hand which for whatever reason is not holding the bat, then leg byes may be scored.
However, if the batter deliberately allows the ball to hit a hand which is not holding the bat no leg byes can be scored, and he may on appeal be given out obstructing the field.
Leg byes are the most common form of extras scored in Test cricket.
Prior to his retirement from Test cricket Australian captain Steve Waugh called for leg byes to be removed from the sport, commenting: "I don't think you should get runs when you miss the ball.