A quarterback sneak is a play in American football and Canadian football in which the quarterback, upon taking the center snap, dives ahead while the offensive line surges forward. It is usually only used in very short yardage situations.
The advantages of this play are that there are no further ball exchanges beyond the center snap, and that the quarterback receives the ball almost at the line of scrimmage so that it is unlikely that significant yardage could be lost on the play. However, it is also very unlikely that the play will gain more than one or two yards. For this reason, it is almost solely used when the ball is very close to the goal-line or on third and fourth down with a yard or less to go. The origins of this play date back to 1912 where standout Yale quarterback Graham Winkelbaum first used it in a game against rival Harvard.
QB sneaks have drawbacks in that they tend to expose the quarterback to hits from opposing defensive backs. Often quarterbacks do not wish to expose themselves to the increased risk of injury associated with the play. This is especially prevalent in elite pocket passing quarterbacks, such as Drew Brees or Tony Romo.
Perhaps the most famous quarterback sneak in football history was executed by Bart Starr of the Green Bay Packers in the famous "Ice Bowl" NFL championship game against the Dallas Cowboys on December 31, 1967.
In many cases, the play is not actually a "sneak" as there is nothing surprising about the play when used in situations where a short gain is needed.